Talk about a wake-up call. President Zelensky, eyeing a possible American retreat from defense commitments on the Continent, is urging Europe to forge an independent military force. “We can’t rule out the possibility that America might say ‘No’ to Europe on issues that threaten it,” the Ukrainian president laments. “Many leaders have talked about Europe that needs its own military — an Army of Europe.” The idea is not without some appeal at first glance.

Mr. Zelensky’s comments Saturday at the Munich Security Conference come amid the uncertainty generated by the Trump administration’s stated ambition to end the war in Ukraine. The fear at Kyiv and other European capitals centers on being left out. “A few days ago, President Trump told me about his conversation with Putin,” Mr. Zelensky gripes. “Not once did he mention that America needs Europe at that table. That says a lot.”

The Ukrainian president is echoing Czechoslovakia’s plea in 1938 when Britain, France, and Italy met at Munich with Germany to decide the fate of the tiny Central European nation, without including the Czechoslovaks. He avers that “Ukraine will never accept deals made behind our backs without our involvement.” He encourages his fellow leaders on the Continent to stiffen their spines, too: “The same rule should apply to all of Europe.”

Mr. Zelensky’s formulation, he says, is “No decisions about Ukraine without Ukraine. No decisions about Europe without Europe.” Noble sentiments, to be sure, but will the European democracies, which have spent decades building up their welfare states and focusing on their citizens’ quality of life at the expense of their militaries, rise to the occasion? More to the point, can they afford the necessary investments in their security infrastructure?

Vice President Vance raised this question at last year’s security conference at Munich, where he groused that America’s “security blanket has allowed European security to atrophy” and chided old Europe for failing to have “taken the initiative in its own security.” Mr. Zelensky’s remarks bring home Mr. Vance’s point. “The old days are over — when America supported Europe just because it always had,” he warns. 

That message follows Mr. Zelensky’s warning that Ukraine has a “low chance” of surviving if America cuts off military aid. It resonates in light of the emerging contours of the peace deal that is shaping up between Presidents Trump and Putin. The two are reportedly headed for a parley in Saudi Arabia. The prospective terms suggest, Bloomberg reports, that the Europeans will “have to shoulder most of the burden for any settlement.” 

The price tag to rearm would prove vast, with an estimate from Bloomberg that “protecting Ukraine and expanding their own militaries” would cost Europe “an additional $3.1 trillion over the next 10 years.” If that sounds expensive, “the cost of inaction could be much higher,” Bloomberg reckons, “with an authoritarian petro-state menacing” the European Union’s “eastern borders and a growing realization that they can’t rely on the White House.” 

That doesn’t necessarily mean Europe will be racing to rearm. Ukraine and Poland are exceptions. Yet Prime Minister Starmer isn’t even committing to boosting British defense spending to 2.5 percent of GDP. President Macron has long backed a European defense force, but France is mired in deficits that will make more spending difficult. Italy, to its credit, asked the EU for a waiver to borrow more to spend on defense, yet that’s no long-term solution.

Even if Europe unsheaths its sword, the blade could prove to be double-edged. The last time Europe launched a military demarche was in 1956 when France and Britain collaborated with Israel to recover the Suez Canal and oust Egypt’s Nasser. America, which was trying to placate Egypt and avoid associations with colonialism, pressured Britain and France to abandon the project. That marked the end of an independent European military.

Were Europe to rearm itself today, would it prove as willing to heed America’s policy dictates? Moreover, who’s to say whether Europe’s leaders would take as friendly an approach to Israel, or, say, follow America’s lead on a tough posture toward Communist China. The prospect is that an American retreat from the burdens of leadership could have unintended consequences. Could “Reveille” in Europe mean “Taps” for American power?