From the campaign trail to the Oval Office, Donald Trump has consistently proposed a kind of portfolio reassessment of America’s alliance system overseas. His initial meeting with British Prime Minister Theresa May went well. But traditional American allies in Europe are still concerned. And Trump means them to be.

Last spring, the New York billionaire famously said that NATO is obsolete, setting off alarm bells from Washington to Warsaw. Just days before his inauguration, in an interview with The Times, he defended that statement — putting it in the past tense — while adding that “countries aren’t paying their fair share.” Now that Trump is president, there are two common interpretations of how this may play out: The first holds that his prior statements on NATO mean little. The second is that Trump is hell-bent on dismantling the Atlantic alliance. The trouble is, both interpretations are mistaken.

Trump himself has indicated more than once how he prefers to approach this issue. In a speech last April hosted by the Center for the National Interest, he reiterated that “our allies are not paying their fair share,” and that “in negotiation, you must be willing to walk.” At the same time, he stated that he wishes to strengthen traditional alliances. This ambition to “reinforce old alliances” was repeated in his inaugural address. Is there a fulcrum here?

His consistently stated position, over a period going back decades, is that the United States spends a great deal on protecting its allies and that its allies do not spend enough on defense.

In the case of NATO, Trump has zeroed in on member state commitments since 2014 to each spend at least two percent of GDP on national defense. Only five out of 28 allies currently meet that target: Britain, Poland, Estonia, Greece, and the United States.

As Britain’s Foreign Secretary, the irrepressible Boris Johnson says:

Trump has a point. It cannot be justified that one NATO ally — America — accounts for about 70 percent of the alliance’s defense spending while the other 27 countries manage only 30 percent between them.

Despite these concerns, the case for NATO’s continued relevance is very strong. Other major powers such as Russia and China would no doubt love to have such a supportive buffering system, keeping their competitors at bay. As Secretary of Defense James Mattis has suggested, if NATO did not exist, we would have to invent it.

But European allies need to understand that beyond the most general statements, the new U.S. president has indicated little detailed commitment to either maintaining or dismantling NATO, as such. On the contrary, he seems to want to keep his options open. If so, he will watch and see what America’s allies do. In a way, the burden of action is now on them.

The administration and allied governments in Europe should therefore consider the framework of any upcoming 2017 NATO summit. Trump is not going to sit through lectures from 28 allied leaders reiterating the need for continued American obedience to a “rules-based liberal order.” He just ran for and won the presidency of the United States on a very different stance, clearly stated.

NATO allies in Europe can help themselves, and make continued U.S. commitment to their security more likely, by taking urgent material action to increase defense spending where it lags — and by cooperating with the United States to revamp this great alliance so that its relevance cannot be questioned.

As Ian Brzezinski wrote in a December essay at RealClearDefense, the United States, Canada, and their European partners can move to invigorate NATO through structural and doctrinal reforms. All members of this alliance face common challenges in relation to Russia, cyber, transnational migration, domestic terrorism, ISIL, and the broader ideology of radical Islam. Allies could do a better job of sharing intelligence and coordinating together against urgent terrorist threats. NATO forces could be upgraded in the direction of improved readiness and speed. The allied decision-making process could certainly be rendered more efficient. And in the face of Moscow’s threats, the nuclear doctrine and posture of the Western alliance needs to be reviewed. All this would leave NATO stronger, updated, and more relevant, as Trump himself suggested last April.

In Defense of NATO

In the coming months and years, the president may come to be further convinced of NATO’s considerable value. Certainly he will have many staunch Republicans on his defense and foreign policy team, willing to make that case. Key European leaders will no doubt continue to make similar arguments. The ones likely to be most persuasive – like Prime Minister Theresa May — will be those who meet their own obligations, and disdain neither NATO nor Trump.

NATO has in fact done tremendous good in the post-Cold War world. It has been crucial in helping to stabilize large tracts of Central Europe as fundamentally peaceful, democratic, market-oriented, and friendly toward the United States. Given the 20th century history of that part of world, that is an historic achievement, and not to be taken for granted. This is very much in the American national interest.

In Afghanistan after 9/11, rallying to America’s side, NATO allies in Canada and Europe made serious material sacrifices — not only in terms of treasure, but even more important, in the blood of their own soldiers. These sacrifices deserve respect.

NATO allies have cooperated in combatting piracy at sea, stabilizing the Balkans, responding to cyber threats — and fighting against ISIL.

And since 2014, in reaction to Russian aggression in the Crimea and Ukraine, many of America’s NATO allies have begun to nudge defense spending upward, and coordinate a deterrent posture aimed at Moscow. Four battalions from Britain, Canada, Germany, and the United States have been sent to Poland and the Baltics, to that end. Economic sanctions on Russia have taken their toll. And only a few weeks ago, the 4th Infantry Division’s 3rd Armored Brigade Combat Team began arriving in Germany and Poland, to deploy throughout the region.

There’s nothing like a little U.S. heavy armor to help clarify a situation. This is what Putin understands. The new administration should reserve the right to engage in hard negotiations with Moscow. These efforts are more likely to be worthwhile and successful if NATO as a whole is militarily strong and diplomatically coordinated. Meanwhile, existing deployments of conventional forces to NATO’s eastern borders should be continued. There must really be no uncertainty as to whether the United States will come to the aid of its treaty allies, such as the Baltic States, if attacked. That particular red line was drawn long ago, and it stands, in the form of NATO’s Article Five. As we saw with Obama’s approach to Syria, an unwillingness to enforce red lines is neither a recipe for peace nor stability. On the contrary, it only encourages misunderstanding and aggression.

But more remains to be done.

The pattern for many years was that Europe outside of Russia gradually demilitarized, while the Western European public came to view peace as the natural and inevitable condition of humanity historically and worldwide. It isn’t. Peace requires constant vigilance. The quality of strategic thought, professional forces, and special operations units with key European allies is often very high. Yet overall defense spending has simply not kept pace with stated and genuine strategic necessities. And to be fair, the same thing has been true of the United States, deadlocked over defense expenditures since 2011. The United States needs to increase its own military budget. And under this new administration, it very likely will. With a Republican president, the longstanding deadlock with Congress over defense spending can and should be broken.

A certain tension in transatlantic relations is really nothing new. It dates back to the very creation of the Western alliance. Europeans have always worried about what the United States might do militarily – or fail to do – outside of Europe, as well as in. Americans, for their part, have always felt the common burden lies disproportionately on their own shoulders. And it does, simply by virtue of scale. Consequently, U.S. leaders wish that Europe would spend more on its own defense. In one of his last speeches as Defense Secretary, the widely respected Robert Gates warned that “if current trends in the decline of European defense capabilities are not halted and reversed, future U.S. political leaders…may not consider the return on America’s investment in NATO worth the cost.” Now here we are; Trump has said something similar. This has caused consternation in European capitals. But you have to admit, he has their attention.

In Defense of the West

There is one other vital point in favor of NATO, which ought to be of special interest to conservatives in particular, even if it doesn’t come up much in policy wonk debates. For most of us who are conservative, the concept of what used to be called Western civilization carries value. We believe in the distinct historical contribution and legacy of the Western world. We aren’t embarrassed to maintain it. Donald Trump, whatever else might be said about him, is one of the surprisingly few U.S. presidential candidates in recent years to speak specifically of Western civilization, and to clarify that Western values are not always universal ones. The fact that this particular statement could be viewed as scandalous is rather bizarre, and an example of what can only be called political correctness.

Insofar as there is any formal secular institution that defends and protects the Western world, specifically, it isn’t the European Union, the United Nations, or any other multilateral organization. It’s NATO. Only NATO links the two great branches of the Western world — North America and Europe — together.

Many of Trump’s core supporters say they look to protect the West. I believe them. That’s exactly why they should preserve and value NATO. In terms of physically defending Western nations in combination from some very real enemies, NATO is all we’ve got.

As it happens, most Trump supporters around the country have no objection to NATO. Quite the contrary. One public opinion poll taken by the Pew Research Center in spring 2016, even as Trump was rolling through the GOP primaries, revealed that 64 percent of his own primary supporters believed that “being a member of NATO is good for the U.S.” Among other Republicans who eventually voted for Trump in the general election, that number was even higher. Trump did not win either the nomination or the general election because of any promise to dismantle NATO. On the contrary, as he himself says, he won on issues of immigration, trade, terrorism, discontent with the status quo, anti-establishment feeling, and a desire for change. So now, as president, the basic direction of American foreign policy – including with regard to NATO – is really up to him. If he keeps central promises made to his core supporters on the concerns that truly matter to them, there’s little reason to believe that NATO’s continued existence need even be an issue.

But all of this depends upon America’s European allies understanding that when it comes to defense spending, the days of cheap talk are over. If those who are lagging expect the United States and its new president to continue reaffirming longstanding commitments to their defense, they should reciprocate, with significant visible increases in their own military budgets. This is particularly true of Germany, Europe’s largest economy. If Trump can point to great progress on the part of Europeans in meeting the commonly agreed upon targets of two percent GDP in the coming years, then both he and the Atlantic alliance will be vindicated. Perhaps out of the heat of disruption, NATO will even thrive.

And if that happens, give the president some credit for kick-starting this process of alliance restructure, burden-sharing, and reform. Because in the end, it will really be our European allies who save NATO, along with themselves.

Colin Dueck is a Professor in the Schar School of Policy and Government at George Mason University, and a non-resident fellow at the Foreign Policy Research Institute. He has published three books on American foreign and national security policies, The Obama Doctrine: American Grand Strategy Today (Oxford 2015), Hard Line: The Republican Party and U.S. Foreign Policy since World War II (Princeton 2010), and Reluctant Crusaders: Power, Culture, and Change in American Grand Strategy (Princeton 2006.) He has worked as a foreign policy advisor on several Republican presidential campaigns.