The North Atlantic Treaty Organization (NATO) is a source of strength for the United States and the nations of Europe, but Europe is endangering NATO’s continued existence through its own actions. If NATO is to remain an effective mutual-assistance defense force, then all the member states must step up and demonstrate their willingness and ability to bear their portion of the burden of alliance membership. Make no mistake, it is Europe’s unwillingness to do so thus far, and not the election of President Donald Trump, that has created the vacuum that invited the present reevaluation of NATO’s future. When it comes to mutual security in Europe, the question that currently haunts the continent is “How much does Europe want it?”

It is true, however, that the United States has some responsibility for the present situation. It helped to found NATO and voluntarily bore a disproportionate economic and military burden within the alliance for much of its history. This was done for a purpose. Following World War II and the profound devastation of the European continent, the relatively untouched United States economy provided Europe with financial resources in the form of the Marshall Plan to help rebuild its industries. The U.S. also carried most of the military burden within the alliance, allowing its European partners to spend more on reconstructing their shattered societies. These efforts only accelerated after the fall of the Soviet Union and the arrival of “the end of history.” Except history never really ends.

The decade of the 1990s, characterized by “peace dividends” and the downsizing of American military forces to include the removal of many forward-based units from Europe, was soon followed by the terror attacks of 9/11. After the Twin Towers fell, NATO as an organization invoked its Article V common-defense clause for the first time, in support of the United States, and began to send expeditionary units to Afghanistan to support U.S.-led counterterrorism efforts there. However, despite increases in activity, there was no real increase in the size of the military forces within most NATO members. Their focus continued to be on internal domestic entitlement spending and supporting the maturation of the European “experiment.” The thought remained that the United States, then spending more than 4 percent of its GDP on defense and national security, would continue to cast its broad security blanket over Europe, where such spending quickly dipped below 2 percent of GDP as a whole.

NATO also continued to grow. Originally founded as a twelve-member organization composed of ten European nations plus Canada and the United States, it has now reached 29 states, with the last, Montenegro, being added in 2017. Who could blame the new member nations for wanting to join NATO? After two generations of slavery under Soviet domination, they clearly wanted freedom and some sense of security in which to build better lives for their people. NATO, with its massive American security blanket, provided it. However, NATO’s broader sense of assurance soon found expression in military complacency as fiscal resources flowed away from national security. “Why worry?” appeared to be the thought; Russia was a weak, ineffectual power, and besides, “the U.S. will provide” had become the accepted mantra.

However, counterterrorism wars in Afghanistan and Iraq distracted the United States’ strategic gaze long enough for Russia to pick off territory in Georgia in 2008 and in Ukraine, including the outright illegal annexation of Crimea, in 2014, with little to no reaction from Europe. While the three small Baltic nations have all increased their defense spending to 2 percent of their GDPs, a majority of NATO’s members, including Germany, the continent’s largest economy, have yet to meet that goal. There is also the looming question surrounding how much each nation contributes to NATO’s operating fund, and the fact that Europe as a whole has not really invested in seriously modernizing its military capabilities. While Russia’s actions bespeak a growing threat to the stability of Europe, it is hard for citizens of the United States to get worked up over the problem when Europeans themselves seem so nonchalant about the issue.

Americans understand that NATO has been a force for good in the world, and they appreciate the fact that the alliance showed solidarity with the U.S. after 9/11, but there is also a slowly opening chasm of understanding with regard to security between Europe and the United States that threatens to fracture the foundation of the alliance. Europe has failed to make the investments necessary to uphold its side of the bargain, and this problem goes far beyond the 2 percent–of-GDP defense-spending issue. Its air forces are largely incapable of operating in advanced anti-access/area-denial environments, which means that in wartime it will be up to the Americans to attack advanced missile sites. European allies have failed to make significant investments in air and missile defense, giving Russia a free pass in these critical technology areas. Legal documents such as the Ottawa Treaty, which limit anti-personnel and other types of mines, are a disadvantage and unrealistic when only one side of a competition plans to adhere to them. Europe has also failed to keep its navies right-sized to wage an anti-submarine campaign in the Atlantic, which means that in wartime Americans will have to fight their way across the Atlantic before they can even land troops on European soil. So far as highly mobile armored units go, most European armies’ tanks are either too few or too antiquated (if they’re not simply non-existent) to fight in a modern land war.

So, as President Trump makes his trip to Brussels and then on to Helsinki, it would be best for European leaders to understand that the future of the alliance lies not in his hands, but theirs. As NATO is a treaty, the United States will not exit the alliance without an action by the Senate, and that is unlikely. The real danger is that the growing American perception that NATO members are not taking their individual responsibilities to the alliance seriously will continue to undermine respect for the organization in the United States, and in Russia. To turn this perception around, NATO’s members must meet the United States halfway, both in their overall defense spending and in the particular investments they make. NATO’s members in Europe and Canada must spend more and modernize their forces. The success of President Trump’s talks with Putin will depend on the degree to which Europe publicly backs Trump’s policies. In the end, when it comes to Europe’s security, the U.S. cannot want it more than Europeans do.