The first year of the second Trump administration has demonstrated—if any more proof were needed—that the days when allies could rely on the United States to uphold world order are over. For the 80 years since the end of World War II, every American president, with the partial exception of Donald Trump during his first term, has been at least somewhat committed to defending a set of close allies, deterring aggression, supporting freedom of navigation and commerce, and upholding international institutions, rules, and laws. U.S. presidents were far from consistent in pursuing these goals, but they all accepted a basic premise that the world was a safer and better place, including for Americans, if the United States devoted significant resources to advancing these aims. Under the second Trump presidency, that is no longer the case.

Trump’s abandonment of traditional American foreign policy has profound implications for the evolving world order and for all countries that have relied so heavily on the United States for decades. Because the reality is that they have no obvious Plan B. Many of Washington’s closest friends are unprepared to deal with a world in which they can no longer count on the United States to help protect them, let alone one in which it becomes an adversary. They are reluctantly starting to recognize the degree to which the world is changing, and they know they need to prepare. But years of dependence, deep internal and regional divisions, and a preference for spending money on social needs over defense have left them without viable near-term options.

For now, most U.S. allies are simply playing for time, trying to preserve as much support from Washington as possible while they contemplate what comes next. They flatter Trump with obsequious praise, give him gifts, host him at lavish events, promise to spend more on defense, accept unbalanced trade deals, pledge (but do not necessarily make) massive investments in the United States, and insist that their alliances with the United States remain viable. And they do so in the hopes that, as after Trump’s first term, he may again be replaced by a president more committed to maintaining Washington’s traditional global role.

Their thinking, however, is wishful. Trump will be in office for three more years, which is more than enough time for the alliance system to degrade further or for adversaries to take advantage of the vacuum the United States has left. Those who believe in alliances, global rules, norms and institutions, and American self-interest in keeping up partnerships can hope that Trump’s approach will not be a lasting one and proceed accordingly. But that may be unwise. Trump represents American attitudes toward foreign policy as much as he shapes them. A generation of failed interventions abroad, growing budget deficits, accumulating debt, and a desire to focus on domestic affairs have left Americans across the political spectrum more reluctant to bear the burdens of global leadership than they have been since before World War II. U.S. allies may not have a Plan B now—but they had better start developing one fast.

In Trump’s first term, the United States’ commitment to supporting its network of global alliances bent but did not break. This was partly because Trump was new to the job, more cautious (in his actions, at least), and not quite ready to revolutionize U.S. foreign policy—but also because he staffed his administration mostly with proponents of traditional foreign and defense policy. His top foreign policy advisers all shared the belief that the United States should be active globally and that it benefits substantially from the political, security, and economic system that had been in place since the 1940s. Notwithstanding his “America first” platform and his own more radical instincts, Trump hesitated throughout most of his first term to take steps that would threaten U.S. global leadership. For example, he considered withdrawing American troops from Germany, Iraq, Japan, South Korea, and Syria but never did so—often because of pushback from his top advisers.

The second Trump administration is different. This time, the so-called globalists are out, and the president is surrounded by people who see most U.S. commitments abroad as a net burden. Vice President JD Vance, Secretary of Defense Pete Hegseth, and Director of National Intelligence Tulsi Gabbard all served in the U.S. military in Iraq and emerged from that experience with deep resentments of U.S. foreign policy elites and the United States’ overseas undertakings. When he was in the Senate, Marco Rubio, who is now serving as both national security adviser and secretary of state, was a strong proponent of standing up to Russia, defending human rights, and providing foreign assistance. Today, however, he appears to have suppressed those convictions to remain relevant and trusted by Trump and the MAGA base. Simply put, the current administration’s worldview appears to be far more influenced by Trump’s long-held beliefs: alliances are an unnecessary burden, autocracies are easier to deal with than democracies, an open trading system is unfair, the United States can sufficiently defend itself without help from other countries, and great powers should have the right to dominate their smaller neighbors—and even to acquire new territory when it is in their interest to do so. The postwar world, built around mostly democratic allies that rely on the United States for security and defense, is gone.

This line of thinking is most evident in the administration’s approach to Europe and NATO. Whereas past presidents expressed an ironclad commitment to NATO’s Article 5, which says........

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