This week’s NATO Summit in Brussels is a peculiar one. It is arguably the least important of the three NATO Summits held since Russia annexed Crimea. The 2014 Wales Summit was significant because of the need to demonstrate unity and to reassure those most alarmed by Russia’s provocations in Central and Eastern Europe. The 2016 Warsaw Summit was notable for establishing the enhanced Forward Presence whereby NATO members would contribute forces to battalion-sized battlegroups in Estonia, Latvia, Lithuania and Poland. The Brussels Summit is supposed to focus on more technical issues, such as EU-NATO cooperation and improvements to military logistics.

And yet a profound sense of crisis seems to pervade the Alliance. The Washington Post Editorial Board recently featured a column that unambiguously declared in its title that “[U.S. President Donald] Trump is bent on wrecking NATO.” On the 2nd of July, a CNN analyst warns that Trump’s “trashing of the NATO alliance” is “dangerous.” Reports circulate of a letter distributed to various NATO capitals from the White House, calling for under-spending allies to develop plans to increase their military capabilities amid rumors that a potential withdrawal of U.S. forces from Europe is under study. Because Trump will meet Russian President Vladimir Putin in Helsinki after the NATO Summit, some worry that the U.S. President will sell allies short in order to strike a deal with Russia.

Everyone should take a deep breath.

To begin with, a sense of precariousness has always shadowed the U.S. military presence in Europe. President Dwight Eisenhower saw U.S. troops in Europe as a temporary expedient and was for five years, by his count, “urging the State Department to put the facts of life before the Europeans concerning reduction (sic) of our forces.” Less than a decade later, Lyndon Johnson confronted an intensifying balance-of-payments crisis that saw massive outflows of gold from the U.S. economy. One tactic he deployed was exerting pressure on West German Chancellor Ludwig Erhard for more offsets (i.e., using U.S. dollars to buy U.S. military equipment) by suggesting that U.S. forces could come home. U.S. troop numbers in Europe remained stable after a partial withdrawal amid the Vietnam War. However, Richard Nixon preferred to rely on U.S. nuclear forces while allies bore the conventional defence burden. More recently, the Obama administration oversaw the withdrawal of combat forces from Germany.

This precariousness has a straightforward geopolitical cause. The United States may be a great power of impressive economic and military power, but it has commitments that span multiple regions around the globe. A rebuilt post-war Europe should eventually have the means to take care of itself. Moreover, the center of gravity in international affairs has steadily been shifting from Europe to Asia thanks to the rise of China. The result is that the United States needs Russia and China to balance one another for the sake of strategic competition, but it must hedge against potential Russian aggression with some presence in Europe. How many troops is enough for this task has never been self-evident.

Still, the U.S. military commitment to Europe has persisted, even though it bears a lighter footprint than in the past. One reason is technological. There may be fewer U.S. conventional forces now in Europe (and in East Asia) than at the height of the Cold War, but they are capable of even greater firepower than before.

Political considerations weigh more heavily, however. Dilemmas abound whenever the United States has considered withdrawing its forces. Allies are often psychologically attached to hosting U.S. military personnel on their territory. Aside from improving local deterrence measures, U.S. forces represent “skin in the game.” An attack on allied territory could kill U.S. forces and thus engage American leaders’ sense of honour or reputation so as to invite an escalatory response.  One dilemma is that some allies might become even more reluctant to spend on their defence if doing so raises the likelihood of U.S. military withdrawals. Another dilemma is that security guarantees are critical for forestalling nuclear proliferation risks. Withdrawing forces might make economic or political sense, but the long-term repercussions could be distasteful. Indeed, it was precisely to head off such risks that some allies appear to be free-riding to this day. Another dilemma is that withdrawing forces can adversely affect power projection capabilities. The United States has forces in Spain, Italy, and Germany in order to perform missions in nearby theatres of operations in North Africa and the Middle East.

How allies respond to potential and actual troop withdrawals depends on their political situation. Frontline allies that face nuclear-armed adversaries have all the reason to be afraid, and so might be tempted to explore the nuclear weapons option. Allies removed from geopolitical threats might in fact welcome withdrawals and be unconvinced that their security is at risk enough to warrant high defense expenditures.

So what does this all mean for the Brussels Summit and, more generally, NATO in the age of Trump? If history is any guide, then the Trump administration will have to wrestle with the same dilemmas that inhibited large-scale withdrawals from Europe in the past. Trump may be unusually combative about having a more equitable defense burden within Europe, but chances are he will get less then what he is calling for and NATO will survive.

Alexander Lanoszka is assistant professor of international relations at the University of Waterloo. He has a co-authored monograph (with Michael A. Hunzeker) on conventional deterrence and Baltic security forthcoming at the Strategic Studies Institute and a book on alliance politics and nuclear proliferation forthcoming at Cornell University Press. You may learn more about his research on www.alexlanoszka.com and follow him on Twitter (@ALanoszka).

The views expressed in this publication are solely those of the author and do not necessarily reflect the views of the EastWest Institute.

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