From its wars in Afghanistan and Iraq to feuds with China in the Far East, the U.S. continues to rely on foreign nations to further its international goals. Many of our most important allies are members of one organization: the European Union. For decades, the EU’s stability has both bolstered American strength abroad and occasionally acted as a check to U.S. power, but within the last decade, the Union has been called into serious question, and if it collapses, the US will become weaker than it ever has before.

Last year, the EU’s long-standing leader, Angela Merkel, retired as Chancellor of Germany, but this power vacuum is only the latest test for the Union. The EU’s signature unifier has long been the euro, a single currency that tied together the economies of all 19 eurozone countries since 1999. Despite boosting economic activity on the continent, the euro also dangerously overextended weaker nations that adopted an overvalued currency relative to their economies. Of course, this wouldn’t be a problem as long as the global economy kept growing, but then the 2008 financial crisis caused all these problems to implode simultaneously.

The Greek Debt Crisis is perhaps the best-known example of the eurozone crisis, but scores of other EU members, including Spain, Portugal and Slovakia, were also plunged into financial hot water that required heavy bailouts from the wealthier members. It also didn’t help that many of the countries who bailed them out were so-called “net contributors” that paid more in taxes to the EU than they received back. Eventually, many people in wealthier member states became sick of sending money elsewhere.

That dynamic was best represented by the 2016 Brexit referendum, where citizens of the UK — then the second biggest net contributor — voted to leave the Union. But Brexit also had a Pandora’s Box effect on other net contributors. In the upcoming French Presidential Election, for example, one of the main frontrunners, Marine Le Pen, has advocated for less unity among EU member states and less economic support for other nations.

What does all of this mean? To some degree, wealthier nations are simply tired of sending their tax dollars to poorer ones without seeing any direct economic benefit themselves, which is understandable. However, the EU’s unravelling should also set off alarm bells in Washington because one of America’s biggest sources of deterrence will collapse. Eastern European nations that border Russia, including Estonia, Latvia and Poland, have long served as strategic military zones allowing the American government to place weapons directly on Russia’s doorstep. But if the EU collapses, individual European countries are simply not powerful enough to deter Russia by themselves. More importantly, many poorer nations who used to rely on the pro-Western EU for economic assistance will become more likely to turn to China for help with its Belt and Road Initiative.

So perhaps we should be worried. But for the time being, German Chancellor Olaf Scholtz is settling in his new job, Marine Le Pen isn’t polling as high as Macron, and the U.K. still hasn’t finished negotiating actually leaving the EU. Perhaps the EU is too important for its members and its collapse is akin to China invading Taiwan: though people may constantly talk about it like it’s going to happen soon, it probably never will.