Germany recently announced plans to renege on its pledge to increase defense spending, and the conventional interpretation is that Chancellor Merkel is standing up to President Trump. But this decision is more than a rebuke of the American president. It represents an affront to NATO itself at a time when the alliance is facing a rising threat from Russia.

Along with all NATO allies, Germany has pledged to aim to spend 2 percent of its gross domestic product (GDP) on domestic defense expenditures by 2024. Until recently, it was making progress toward that goal.

Let’s give credit where credit is due: President Trump has been taking on our allies—and NATO in particular—over burden-sharing since his 2016 campaign. But encouraging our allies to shoulder more of the burden of collective defense has been a long-standing U.S. policy goal. While Trump’s rhetoric is more bombastic, his predecessors also worked to achieve greater burden-sharing.

The Bush Administration pressured NATO countries to increase their defense spending to an “unofficial floor” of 2 percent of GDP in 2006, as the alliance ramped up its military operations in Afghanistan. Despite having broad differences over foreign policy with his predecessor, President Obama supported the goal as well, especially after the Russian invasion of Crimea renewed the purpose of NATO’s mission and the importance of adequate defense spending. Alliance leaders officially agreed to the 2 percent goal in 2014.

Perhaps more important, a broad and bipartisan majority of the American people want NATO allies to do more. The Reagan Institute’s National Defense Survey from last fall laid bare this reality—alongside deep support for the alliance itself. While 60 percent of respondents expressed a favorable view of NATO, 61 percent said they think our allies should be doing more.

Ultimately, beyond all the rhetoric and bombast, the underlying question about how much our allies spend on defense speaks to the worth of the NATO alliance itself. With leaders gathering in Washington this week for a ministerial meeting and to celebrate the 70^th anniversary of NATO, now is a good opportunity to reexamine the value of the alliance as a bulwark of transatlantic security.

Defenders of NATO ought not reflexively reject President Trump’s questions about the alliance. If there is a case to be made for NATO, we should make it. And if the alliance is worth it, NATO countries should meet their commitments—not just for the sake of the alliance, but to meet the threats we face together.

The threat to NATO members could not be more clear. Vladimir Putin’s revanchist ambitions manifest themselves across all domains, from military aggression in occupying foreign territory to disinformation campaigns that undermine democracy, and some of our NATO allies understand the Russian threat better than others. One sign of this awareness is that four of the six European countries that have met the 2 percent threshold are some of the closest to Russia geographically: Estonia, Poland, Latvia, and Lithuania.

Geography aside, there is no more important player on the European continent than Germany. As the continent’s largest economy and its political leader, Germany should be leading the effort among NATO countries to increase defense spending—not undermining it. U.S. Ambassador to Germany Richard Grenell stressed the importance of German leadership in his response to the announcement on cutting defense spending: “That the German government would even be considering reducing its already unacceptable commitments to military readiness is a worrisome signal to Germany’s 28 NATO allies.”

It’s no secret that defense spending is politically unpopular in Germany. But here, Chancellor Merkel could take a cue from President Reagan. In a 1983 speech to the American people from the Oval Office promoting increased defense spending and a restoration of our nation’s military strength, Reagan explained, “Every item in our defense program—our ships, our tanks, our planes, our funds for training and spare parts—is  intended for one all-important purpose: to keep the peace.”

This is true of NATO defense spending as well. And if Chancellor Merkel shares this goal, she should make the case to the German people. But if scoring domestic political points is more important, the real winner here is Vladimir Putin, who will view this neglect of NATO as a sign of weakness of the alliance.

When it comes to the politics of defense commitments, the fundamental question is clear: Are our European allies more concerned with standing up to President Trump or Vladimir Putin?