When he begins his second term as president, Donald Trump will inherit a world far more hostile to U.S. interests than the one he left behind four years ago. China has intensified its efforts to expand its military, political, and economic influence worldwide. Russia is fighting a brutal and unjustified war in Ukraine. Iran remains undeterred in its campaign to destroy Israel, dominate the Middle East, and develop a nuclear weapons capability. And these three U.S. adversaries, along with North Korea, are now working together more closely than ever to undermine the U.S.-led order that has underpinned Western peace and prosperity for nearly a century.

The Biden administration sought to manage these threats through engagement and accommodation. But today’s revanchist powers do not seek deeper integration with the existing international order; they reject its very basis. They draw strength from American weakness, and their appetite for hegemony has only grown with the eating.

Many in Washington acknowledge the threat but use it to justify existing domestic policy priorities that have little to do with the systemic competition underway. They pay lip service to the reality of great-power competition but shirk from investing in the hard power on which such competition is actually based. The costs of these mistaken assumptions have become evident. But the response to four years of weakness must not be four years of isolation.

Even though the competition with China and Russia is a global challenge, Trump will no doubt hear from some that he should prioritize a single theater and downgrade U.S. interests and commitments elsewhere. Most of these voices will argue for focusing on Asia at the expense of interests in Europe or the Middle East. Such thinking is commonplace among both isolationist conservatives who indulge the fantasy of “Fortress America” and progressive liberals who mistake internationalism for an end in itself. The right has retrenched in the face of Russian aggression in Europe, while the left has demonstrated a chronic allergy to deterring Iran and supporting Israel. Neither camp has committed to maintaining the military superiority or sustaining the alliances needed to contest revisionist powers. If the United States continues to retreat, its enemies will be only too happy to fill the void.

Trump would be wise to build his foreign policy on the enduring cornerstone of U.S. leadership: hard power. To reverse the neglect of military strength, his administration must commit to a significant and sustained increase in defense spending, generational investments in the defense industrial base, and urgent reforms to speed the United States’ development of new capabilities and to expand allies’ and partners’ access to them.

As it takes these steps, the administration will face calls from within the Republican Party to give up on American primacy. It must reject them. To pretend that the United States can focus on just one threat at a time, that its credibility is divisible, or that it can afford to shrug off faraway chaos as irrelevant is to ignore its global interests and its adversaries’ global designs. America will not be made great again by those who simply want to manage its decline.

A FALSE CHOICE

China poses the gravest long-term challenge to U.S. interests. But although successive presidents have acknowledged this reality, their actual policies have been inconsistent. Administrations have failed even to agree on the basic objective of competition with China. Is it merely a race to produce more widgets? An opportunity to sell more American soybeans, semiconductors, solar panels, and electric vehicles? Or is it a contest over the future of the international order? The Trump administration must recognize the gravity of this geopolitical struggle and invest accordingly.

In so doing, it must not repeat the mistakes of President Barack Obama’s so-called pivot to Asia. The Obama administration failed to back up its policy with sufficient investments in U.S. military power. Inverting the traditional relationship between strategy and budgets, it prioritized defense cuts for their own sake, abandoning the decades-long “two-war” construct of force planning. The bipartisan Budget Control Act of 2011 compounded this mistake and harmed military readiness.

Partners in Asia came to understand what the pivot meant for them: that they would receive a larger slice of a shrinking pie of American attention and capabilities. Partners in Europe, for their part, were not happy to see Washington ignore the Russian threat. Republicans who consider Ukraine a distraction from the Indo-Pacific should recall what happened the last time a president sought to reprioritize one region by withdrawing from another. In the Middle East, Obama’s premature withdrawal from Iraq left a vacuum for Iran and the Islamic State (also known as ISIS) to fill, and the ensuing chaos there consumed Washington for years. By 2014, as Obama struggled to consummate the pivot to Asia, dithered on the Middle East, and failed to enforce his own “redline” on Syria’s use of chemical weapons, Russian President Vladimir Putin invaded eastern Ukraine and seized Crimea.

Standing up to China will require Trump to reject the myopic advice that he prioritize that challenge by abandoning Ukraine. A Russian victory would not only damage the United States’ interest in European security and increase U.S. military requirements in Europe; it would also compound the threats from China, Iran, and North Korea. Indeed, hesitation in the face of Putin’s aggression has already made these interconnected challenges more acute. The George W. Bush administration’s failure to respond forcefully to Putin’s invasion of Georgia in 2008 was a missed opportunity to nip Russian aggression in the bud. Obama’s “reset” with Russia doubled down on this miscalculation, snuffing out hope for a concerted Western response to Russian aggression. In pursuit of arms control negotiations, he pulled his punches as Putin grew emboldened. This weakness continued in Obama’s tepid response to the 2014 invasion of Ukraine.

Trump deserves credit for reversing the Obama administration’s limitations on assistance to Ukraine and authorizing the transfer of lethal weapons to Kyiv. During the first Trump administration, the United States used force against Russia’s ally Syria to at last enforce the redline against chemical weapons, killed hundreds of Russian mercenaries who threatened U.S. forces in Syria, and increased U.S. energy production to counter Russia’s weaponization of its oil and gas reserves. But Trump sometimes undermined these tough policies through his words and deeds. He courted Putin, he treated allies and alliance commitments erratically and sometimes with hostility, and in 2019 he withheld $400 million in security assistance to Ukraine. These public episodes raised doubts about whether the United States was committed to standing up to Russian aggression, even when it actually did so.

Despite Biden’s tough campaign rhetoric about Russia, his policy of détente with the Kremlin resembled Obama’s reset. Immediately after taking office in 2021, Biden signed a five-year extension to the New START treaty, giving up leverage over Russia that he could have used to negotiate a better agreement and tying the United States’ hands as nuclear threats from China and North Korea grew. In June of that year, he, too, withheld critical security assistance from Ukraine. And in August, he oversaw the disastrous U.S. withdrawal from Afghanistan, which no doubt encouraged Russia to further test the limits of American resolve. The Biden administration’s apparent belief that Putin’s imperial ambitions could be managed with arms control and U.S. restraint was not dissimilar to right-wing isolationists’ misplaced interest in accommodating Russia.

As it became clear that Putin would launch a full-scale invasion of Ukraine, I urged Biden to offer meaningful lethal aid to Ukraine and expand the U.S. military footprint in Europe. But the president demurred. Even after the invasion, the Biden administration’s assistance to Ukraine was beset by hesitation, needless restrictions, and endless deliberation. These delays repeatedly ceded the initiative to Moscow and diluted the effectiveness of U.S. aid, prolonging the conflict and diminishing Kyiv’s negotiating leverage. The weakness of the Biden administration’s policies was drowned out by frenzied attention to some Republicans’ objections to supporting Ukraine. Their misguided opposition delayed passage of the “national security supplemental,” but when the chips were down, Senate Republicans overwhelmingly supported the measure, as did many Republicans in the House. Congress passed the supplemental in April 2024. And not a single Republican legislator who voted for Ukraine lost a primary.

Despite legitimate misgivings about Biden’s approach, a majority of my GOP colleagues appreciated that support for Ukraine is an investment in U.S. national security. They recognized that most of the money was going to the U.S. defense industrial base or military and that this security assistance, a mere fraction of the annual defense budget, was helping Ukraine degrade the military of a common adversary. But more work is required. For now, Putin’s indifference to his own people’s suffering has allowed him to increase his defense industrial base’s capacity to pump arms and soldiers into Ukraine. His ability to do this in perpetuity is questionable; Russian victory is inevitable only if the West abandons Ukraine.

THE ALLIED ADVANTAGE

Trump will hear from neo-isolationists who discount the importance of American allies to American prosperity, ignore the need for the United States’ credibility among fence sitters in critical regions, and misunderstand the basic requirements of the U.S. military to deter or win faraway conflicts. Their arguments elide the fact that the enemy gets a vote, too, and may decide to confront the United States simultaneously on multiple fronts, at which point allies become more valuable than ever.

In Europe, Trump will find encouraging progress. After major surges in their defense budgets, U.S. allies on the continent now spend 18 percent more than they did a year ago, a far greater increase than the United States’. More than two-thirds of NATO members now meet or exceed the alliance’s target of spending at least two percent of GDP on defense. This progress is not without exception. One of the West’s most glaring vulnerabilities to the influence of Russia—and China and Iran—is Hungary’s self-abnegating obeisance to those countries.

But aside from this noisy exception, it is not lost on the United States’ European allies that Trump called on them to take hard power and burden sharing more seriously. NATO allies are also buying American, and since January 2022 have ordered more than $185 billion of modern U.S. weapons systems. But Trump will be right to encourage allies to do more. At the next NATO summit, allies should set a higher defense-spending target of three percent of GDP and commit to increasing their base budgets accordingly.

The most inconvenient truth for those calling on Trump to abandon Europe is that European allies recognize the growing links between China and Russia and increasingly see China as a “systemic rival.” During a visit to the Philippines in 2023, European Commission President Ursula von der Leyen noted that “security in Europe and security in the Indo-Pacific is indivisible.” U.S. allies in Asia understand the same thing. As Hsiao Bi-khim put it in 2023, when she was Taiwan’s representative in Washington, “Ukraine’s survival is Taiwan’s survival.”

The unwillingness of the “Asia first” crowd to welcome European allies’ progress is curious. They ignore a glaring need to work with allies to counter Chinese threats to shared interests, raising the question of whether they are really interested in contesting China after all. Some even seem to have seized on the need to counter China as a rationale for the United States to abdicate leadership everywhere else, suggesting that “Asia first” is merely an excuse for underlying isolationism.

These critics ignore the growing strategic alignment of China and Russia, Russia’s own influence in Asia (including its increasingly capable Pacific fleet), and the inescapable reality that U.S. competition with both powers is global. In the Middle East, for example, Russia has undermined U.S. interests for years through its intervention in Syria and partnership with Iran. Putin’s use of Iranian attack drones in Ukraine should have come as no surprise: the West’s collective failure to stand up to Iran earlier has allowed it to become a more powerful partner to China and Russia. Beyond embracing Iran, the two countries have also sought to deepen their relationship with traditional U.S. partners in the region.

China has for years sought to drive a wedge between the United States and its partners. It is tragic that the “Asia first” crowd would so obviously play into Beijing’s hands, just as previous administrations that had turned their back on allies in the Middle East opened the door to Chinese influence in that critical region.

HOLIDAY FROM HARD POWER

The U.S. government spends nearly $900 billion annually on defense, but considering the total amount of federal spending, the challenges facing the United States, the country’s global military requirements, and the return on investment in hard power, this is not nearly enough. Defense is projected to account for 12.8 percent of federal spending in 2025, less than the share devoted to servicing the national debt. And each year, a larger portion of the defense budget pays for things other than weapons; nearly 45 percent of it now goes toward pay and benefits.

The situation is grave. According to an estimate by the American Enterprise Institute that rightly incorporates the paramilitary functions of China’s space program and coast guard, China spends $711 billion a year on its military. And in March 2024, Chinese officials announced a 7.2 percent increase in defense spending. The Biden administration, by contrast, requested real-dollar cuts to military spending year after year. If defense budgets cannot even keep up with inflation, how can Washington keep up with the “pacing threat” of China?

Moreover, because its immediate military objectives are focused on countering the United States in the Indo-Pacific, China, unlike the United States, mainly needs to allocate resources to its own backyard. The requirements of global power projection necessarily spread U.S. defense expenditures far thinner. Although bipartisan recognition of U.S. interests in Asia is welcome, it is reckless for U.S. politicians to visit Taipei or talk tough about China if they are unwilling to invest in the capabilities necessary to back up U.S. commitments.

The United States needs a military that can handle multiple increasingly coordinated threats at once. Without one, a president will likely hesitate to expend limited resources on one threat at the expense of others, thereby ceding initiative or victory to an adversary. The United States must get back to budgets that are informed by strategy and a force-planning construct that imagines fighting more than one war at once.

And yet for years, congressional opponents of military spending absurdly insisted that there be parity between increases in defense spending and increases in nondefense discretionary spending, holding military power hostage to pet political projects. Meanwhile, domestic mandatory spending skyrocketed, and massive expenditures that circumvented the annual bipartisan appropriations process, such as the ironically named Inflation Reduction Act, included not a penny for defense.

Isolationists on both ends of the political spectrum unwittingly validate this artifice when they peddle the fiction that military superiority is cost-prohibitive or even provocative, that the United States must accept decline as inevitable, or even that the effects of waning influence won’t be that bad. Calls for “disentanglement,” “leading from behind,” and “hard prioritization”—amplified by historical amnesia—amount to defeatism. The United States’ security and prosperity are rooted in military primacy. Preserving that decisive superiority is costly, but neglecting it comes with far steeper costs.

Past levels of U.S. defense spending put today’s needs into perspective. During World War II, U.S. defense spending hit 37 percent of GDP. During the Korean War, it reached 13.8 percent. At the height of the Vietnam War, in 1968, it stood at 9.1 percent. The defense buildup under President Ronald Reagan, which followed a low of 4.5 percent of GDP during the Carter administration, peaked at only 6 percent. In 2023, the United States spent 3 percent of GDP on defense.

During this American holiday from hard power, China and Russia have invested in asymmetric capabilities to offset the U.S. military edge. Today, their munitions in many categories can outrange U.S. versions, and their production can outpace the United States’. This is to say nothing of their numerical advantage in key platforms, from missiles to surface vessels. Quantity has a quality of its own. What’s more, the wars of the future may well last longer and require far more munitions than policymakers have assumed, as both Israeli and Ukrainian munitions-expenditure rates suggest. U.S. stockpiles are insufficient to meet such a demand. For years, the military services have shortchanged munitions in favor of new weapons systems and platforms. This is not to downplay the need to modernize major weapons systems but to highlight the harmful tradeoffs imposed by inadequate defense budgets.

If the United States finds itself embroiled in conflict in a far-flung theater, it will also have difficulty resupplying its forces. China, for one, intends to contest U.S. logistical supply lines. This reality, combined with the possibility of being challenged in different parts of the world simultaneously, doesn’t just require building larger inventories of platforms and munitions. It also requires ensuring that such capabilities are pre-positioned in multiple theaters. That, in turn, requires securing basing, access, and overflight rights—yet another argument for strengthening U.S. alliances globally.

Thanks to Republican efforts, the national security supplemental included necessary investments to expand the production capacity of key items, such as solid rocket motors, needed for long-range munitions and interceptors. But my efforts with Susan Collins, the vice chair of the Senate Appropriations Committee, to expand this investment beyond the Biden administration’s request faced the same headwinds as our annual campaign to build bipartisan support for greater overall defense spending. In fiscal year 2023, congressional Republicans overcame Democrats’ insistence on parity between defense and nondefense discretionary spending. That was a step in the right direction, but Democrats need to permanently abandon this misguided obsession. The demands of U.S. national security are not political bargaining chips.

Progress on this front begins with real increases in defense spending. In 2018, the Commission on the National Defense Strategy—a bipartisan group of defense experts established by Congress—stressed that preserving the United States’ military edge would require sustained real growth in the defense budget of between three percent and five percent. By 2024, the commission, noting the worsening threats, called that range a “bare minimum” and advocated budgets big enough to “support efforts commensurate with the U.S. national effort seen during the Cold War.”

The Trump administration must heed the commission’s warning. To pay for increased defense budgets, it should take an axe to extravagant nondefense discretionary spending and tackle the unsustainable level of mandatory spending on entitlements that is driving the deficit. It should also reform an overly burdensome economic regulatory environment to counteract these drags with higher growth and revenue.

THE ARSENAL OF DEMOCRACY

At the same time, the United States must tend to its atrophied defense industrial base. The Pentagon, Congress, and industry all deserve blame for its sorry state. The Defense Department and Congress have sent inconsistent demand signals to industry, which has discouraged companies from investing in expanded production capacities and resilient supply chains. To solve the problem, administrations must submit defense-budget requests that are big enough to meet the United States’ true military needs. Congress must pass appropriations bills on time. If it doesn’t, the resulting “continuing resolutions”—temporary measures to keep the federal government funded—delay contracts and prohibit new program starts.

Congress has given the Pentagon the authority to sign multiyear procurement contracts—which limit the uncertainty sometimes caused by the annual appropriations process—for certain critical munitions. This approach and the money to back it up should both be extended to other long-range munitions and missile defense interceptors for which long-term demand is nearly certain. To expand production capacity, the Pentagon can also use the Defense Production Act, a 1950 law that allows the government to prioritize and steer resources toward the production of goods for national defense. Unfortunately, recent administrations have used this authority for purposes that have nothing to do with national security. Biden, for instance, invoked it for the production of solar panels. It is past time to put the “defense” back into the Defense Production Act.

But industry cannot simply wait for the government to invest. I am sympathetic to companies’ frustrations with a slow federal bureaucracy and an inconsistent Congress, but only to a point. It should be obvious to private-sector leaders that the need for air and missile defense interceptors, long-range munitions, and other critical weapons is steadily rising and unlikely to abate anytime soon. The demand is inevitable. Industry should be leaning forward to meet it. Trump should put the Pentagon and the defense industry on notice about the need to act.

Bureaucracy has also stifled innovation even when its military utility is obvious. The Defense Department is to be commended for its Replicator Initiative, a program designed to hasten the adoption of emerging military technologies, but creating an entirely new acquisition process raises the question of why the Pentagon doesn’t just fix its existing one. The department must figure out how to adopt and integrate disruptive technologies as soon as possible, or else the military will find itself on the receiving end of smarter, cheaper, more autonomous unmanned systems fielded by adversaries moving faster than the speed of bureaucracy.

Just the contracting process for weapons—to say nothing of actually building them—moves unbelievably slowly. For weapons systems that cost more than $100 million, it takes an average of more than ten months between releasing a final solicitation for bids and awarding a contract. Foreign military sales move even slower: it takes an average of 18 months for American partners to get U.S. weapons under contract. The Biden administration made a halfhearted attempt to reform the foreign military sales process, but making it more efficient needs to be a joint priority for the secretary of defense and secretary of state. The arsenal of democracy will not endure if the United States’ own inefficiencies—or the opposition of vocal minorities in Congress—dissuade vulnerable allies from buying American.

The Trump administration should consider dramatically streamlining the process for commonly used munitions or preemptively building up inventories for export. The military should also consider maintaining larger stockpiles of weapons that can be more easily shared with allies and partners in times of crisis. Once the shooting starts, the time to build production capacity has passed.

To build an allied coalition of cutting-edge forces that can work together seamlessly, the United States must also be willing to share more technology. AUKUS, the United States’ security partnership with Australia and the United Kingdom, can be a model for greater technology sharing with other trustworthy allies and partners. Defense-technology transfer isn’t an act of charity; increasingly, it is a two-way street, with allies such as Australia, Finland, Israel, Japan, Norway, South Korea, and Sweden bringing cutting-edge capabilities to the table. The United States should expand coproduction with its allies and encourage them to produce interoperable capabilities, thereby reducing costs, shoring up inventories, improving supply chain resilience, and enhancing collective capacity to compete with China.

THE ECONOMIC ELEMENT

The United States would be foolish to compete with China by itself. U.S. allies and partners represent a significant share of the global economy. It would be simply unaffordable to replicate all their supply chains domestically.

Obama deserves credit for negotiating the Trans-Pacific Partnership with U.S. allies in Asia, and I do not regret working with him to overcome the objections of protectionist Democrats in Congress. Beyond lowering trade barriers and expanding market access for U.S. companies, the agreement was designed to establish favorable rules of the road for international trade in a critical region of the world. The parties to the proposed agreement represented 40 percent of the global economy. But rather than strengthen and harness the power of Western economies, the first Trump administration and then the Biden administration sometimes actively antagonized them, including with tariffs that have strained relationships with allies and tested the patience of American consumers. This abdication was an invitation for China to expand its economic influence in Asia at the United States’ expense.

There is plenty of evidence that the globalist optimism of the 1990s was unfounded. Welcoming China and Russia into the World Trade Organization has not transformed their governments or economies, at least not in ways beneficial to the free world. Rather, both countries have exploited and undermined this and other international economic institutions. I am not naive about the downsides of international trade, but there is no question that free markets and free trade have been responsible for much of the United States’ prosperity. That’s why the United States and like-minded free-market economies must work together to reform the international trading system to protect U.S. interests from predatory trade practices—not abandon the system entirely. Without U.S. leadership in this area, there is little question that Beijing will be able to rewrite the rules of trade on its own terms.

Although flagging military primacy is the most glaring impediment to national security, the United States cannot neglect the role of foreign aid, either. As the former chair of the Senate appropriations subcommittee responsible for foreign assistance, I take seriously James Mattis’s admonition when he was head of U.S. Central Command that if Congress shortchanged diplomacy and foreign aid, he would “need to buy more ammunition.” Unfortunately, these important tools of American power are increasingly divorced from American strategic interests. It is past time to integrate foreign assistance more deliberately into great-power competition—for example, by working with allies to present credible alternatives to China’s Belt and Road Initiative.

NO TIME TO TURN INWARD

In January 1934, William Borah, a Republican senator from Idaho and an outspoken isolationist, addressed a meeting of the Council on Foreign Relations in New York. Because peace had prevailed for 15 years following the end of World War I, Borah argued, global military spending was excessive. Tensions between European powers, he insisted, could not be solved by outsiders: “It will be a long time, I venture to believe, before there will be any necessity or any justification for the United States engaging in a foreign war.”

Of course, by the end of the 1930s, the Nazi conquest of Europe had driven a dramatic swing in U.S. public opinion away from Borah’s isolationist daydream. By May 1940, as German forces invaded France, 94 percent of Americans supported any and all necessary investments in national defense. By June, more than 70 percent favored the draft.

The United States saw the light during World War II. But must it take another conquest of a close ally before the country turns its belated attention to the requirements of national defense? Isolation is no better a strategy today than it was on the eve of World War II. Today, in fact, in the face of linked threats even more potent than the Axis powers, a failure to uphold U.S. primacy would be even more catastrophically absurd than was the refusal to assume that responsibility 85 years ago. The last time around, the naive abdication of the requirements of national defense made reviving the arsenal of democracy on a short timeline unnecessarily difficult. As Admiral Harold Stark, then the chief of naval operations, observed in 1940, “Dollars cannot buy yesterday.”

The United States urgently needs to reach a bipartisan consensus on the centrality of hard power to U.S. foreign policy. This fact must override both left-wing faith in hollow internationalism and right-wing flirtation with isolation and decline. The time to restore American hard power is now.