They delivered dueling speeches on Saturday at the Munich Security Conference. First came Angela Merkel, the German chancellor. She offered a defense of the institutions the United States designed and supported for seven decades, countries with shared values joining together to promote stability and prosperity. The centerpiece has been the North Atlantic Treaty Organization.

Vice President Mike Pence followed with a wholly different perspective. He appeared inclined to make demands, allies measured by their willingness to serve American interests as defined by the Trump White House. In the aftermath, the director of the Berlin office of the German Marshall Fund made a telling remark to the New York Times: “If an alliance becomes unilateral and transactional, then it is no longer an alliance.”

A prestigious conference in Germany can seem far removed. Yet something worrisome is happening that merits close attention. President Trump isn’t just badgering NATO allies to boost their defense budgets. He is calling into question the worth of such institutions, seemingly convinced the country would be better served on its own. The approach of the vice president reinforced the impression of an administration desiring to break away.

That is a monumental choice. Yet neither the president nor the vice president has taken time to flesh out a strategic argument for why.

The vice president actually praised his boss for restoring American leadership. As Anne Applebaum of Washington Post reiterated on this page on Wednesday, leadership involves followers, and in this instance, they are becoming reluctant, if not scarce. Consider the disturbing words of the Russian foreign minister, “We see new cracks forming and old cracks deepening.”

The heightened stresses and strains are the work of the president, acting in ways more in line with the interests of adversaries such as Russia or China. Even worse is that the president fails to see the clear and long-standing American advantage in working with allies and partners. Vladimir Putin and Xi Jinping would like few things more than to have the equivalent as a way to build influence and exert power. So, no doubt, they are pleased with second best, the president encouraging divisions they can seek to exploit.

One German official told the Times, “No one any longer believes that Trump cares about the views or interests of the allies. It’s broken.” Angela Merkel illustrated the point as she discussed the president’s threat to impose tariffs on German cars as a matter of national security. She reminded that BMW employs roughly 10,000 at its plant in South Carolina. Is that a problem for the American workers there? Or for the country’s security?

The president seems oblivious, as did the vice president in Warsaw before the meeting in Munich. The vice president failed to utter a critical word about the leaders of Hungary and Poland who have been weakening democracy and the rule of law in their countries. Ordinarily, an American president or vice president would stand up for shared values.

This is how things erode, in this instance, leaders neglecting what matters. The point isn’t to deny the imperfections in NATO, or in its strategic cousin, the European Union. Partners will disagree. They will fall short. At the same time, the alliance has been a signal achievement, bringing a long peace to a Europe battered by world wars. The alliance is about more than defense. It represents the freedoms and opportunities enjoyed here and across the Atlantic.

Whatever the challenge, climate change, migration, trade with China, a more aggressive Russia, North Korea or Iran, Americans are in a better position with allies. The worry watching the vice president in Munich is how much damage will the Trump White House inflict.