President Donald Trump’s trip to Europe for the NATO summit was supposed to reassure NATO’s members—and remind NATO’s enemy—that the United States remains committed to the alliance. Specifically, administration officials indicated that Trump would reinforce U.S. support for Article V of the North Atlantic Treaty, which declares, “an armed attack against one or more of them…shall be considered an attack against them all.” But Trump never defended Article V. Worse, we recently learned that he actually removed a reference to Article V from his remarks in Brussels—remarks that when drafted read, “I stand here before you with a clear message: the U.S. commitment to the NATO alliance and to Article V is unwavering.” When the speech was delivered, that sentence was somehow deleted.

This is a terrible diplomatic failure—“mistake” is the wrong word because it appears Trump chose not to say what needed to be said—that carries serious military and security implications. Moreover, it’s a failure of execution within a failure of comprehension.

What do I mean by “comprehension”? President Trump needed to reinforce America’s commitment to Article V because of Candidate Trump’s comments about NATO during the campaign—comments that reflect a fundamental lack of understanding about the most successful military alliance in history.

Recall that Candidate Trump described NATO as “obsolete…because of the fact they don't focus on terrorism.” He even suggested he would come to the defense of NATO members under attack—an ironclad requirement of the North Atlantic Treaty—only if they had “fulfilled their obligations to us.”

Russia’s aggressive behavior under Vladimir Putin—from its outrageous claims in the Arctic (made in a brazen military context), to its constant violations of NATO airspace, to its breach of the INF Treaty and CFE Treaty, to its invasions and annexations of parts of Ukraine and Georgia (both NATO aspirants), to its relentless cyberattacks against NATO members, to its misinformation-influence campaigns targeting the electoral process of NATO members, to its attempt to overturn the settled outcomes of the Cold War, to its swelling military arsenal and mushrooming defense spending—proves that NATO is anything but obsolete. Indeed, NATO’s Article V commitment is more important today than at any time since 1991.

As to NATO and the war on terror, the only time NATO has invoked Article V was in response to the terrorist attacks of September 11, 2001. Ever since, the alliance has devoted military resources, diplomatic energy, economic treasure and human life to fighting terrorism. For anyone in the Trump campaign who cared to look, NATO documents in 2002, 2004, 2006, 2008, 2009, 2010, 2012, 2014 and 2016 affirmed and reaffirmed NATO’s commitment to fighting terrorism. European and Canadian members of NATO have lost 1,046 troops fighting terrorism in Afghanistan. And NATO members form the core of the campaign against ISIS.

While it’s appropriate to ask hard questions about Europe’s contribution to the common defense, those who ask such questions must also answer a question: Would they rather the United States face a revisionist Russia and a virulent jihadist assault on the West alone? “If we didn’t have NATO today, we’d need to create it,” Defense Secretary James Mattis concludes. “NATO is vital to our interests.”

Thanks to Mattis, Trump began to soften his anti-NATO rhetoric after the election. “We strongly support NATO, an alliance forged through the bonds of two world wars that dethroned fascism, and a Cold War that defeated communism,” he declared, generously adding, NATO is “no longer obsolete.”

However, his continued cageyness about—and apparent disregard for—Article V leaves room for doubt inside the alliance and miscalculation inside the Kremlin.

Trump’s zig-zagging rhetoric suggests unpredictability, which suggests undependability, which is not what NATO needs.

Regrettably, less-than-fulsome support for NATO from Washington predates the Trump presidency.

President Barack Obama unilaterally pulled the plug on missile-defense plans to protect Europe from Iran—plans endorsed by the entire alliance—in hopes of placating Moscow and pursuing a “Russian reset.” Instead of planting permanent ground-based defenses in Poland and support radars in the Czech Republic, Obama deployed an impermanent variant of a sea-based missile-defense system. Worse, he did so “without even informing the Polish prime minister in a timely manner,” as historian George Weigel recalls. Poland’s Defense Ministry called Obama’s reversal “catastrophic.” The Czechs angrily rejected Obama’s plans as “a consolation prize.”

In 2011, Obama put a time limit on America’s commitment to NATO’s intervention in Libya. In fact, when he grudgingly agreed to extend operations after an urgent request from the alliance, a NATO official emphasized that the extension of U.S. air power “expires on Monday”—a bruising metaphor for American leadership under Obama.

In 2013, after the French military requested U.S. air support in its fight against jihadists in Mali, the Obama administration sent Paris an invoice. That same year, when Obama erased his own “red line” in Syria, the French were forced to stand down and shelve plans for punitive action against Assad.

Also in 2013, the Obama administration withdrew the last remaining American tanks from Europe—the first time since 1944 that Europe was left unprotected by American tanks. That shortsighted decision sent precisely the wrong message—to NATO and Moscow—and has been corrected.

In 2016, Obama publicly criticized Britain and France for their handling of Libya and Syria—noting in Trumpian fashion that “Free riders aggravate me,” in the very same breath that he braggingly recalled how he lectured Britain’s prime minister, “You have to pay your fair share.”

While the average American wouldn’t know it from Trump’s words (spoken and unspoken) or Obama’s actions, NATO plays an important role for its most important member: the United States. NATO represents a readymade structure where Washington builds coalitions, a bridge to global hotspots, and a force-multiplier for U.S. power. As several former NATO commanders conclude, “There is no hope for the U.S. to sustain its role as the world’s sole superpower without the Europeans as allies.” The generals know what the politicians ignore: Protecting our interests and our civilization, ensuring the free flow of goods and resources, preserving a liberal international order, defending the global commons, responding to natural disasters and manmade chaos—these missions depend on NATO infrastructure in places like Lakenheath, Ramstein, Morón, Aviano and Incirlik.

Even more important, the deterrent represented by Article V is an insurance policy against worst-case scenarios. For America, NATO diminishes the likelihood of another European conflict triggering another great-power war. For NATO’s other members, NATO is a security guarantee backed by America. Without that guarantee, there’s no security, as history has a way of reminding those on the outside looking in, from Cold War Hungary to post-Cold War Ukraine. Trump must make America’s commitment to Article V unequivocal and undeniable. Because his NATO summit speech was so deafeningly silent on Article V, his statement during a June press conference that “Absolutely, I’d be committed to Article V” comes across as an afterthought—and is simply not good enough.

The president’s recent visit to Poland provided the perfect opportunity, timing and place to correct this mistake (again). And to his credit, he used his Warsaw address to reaffirm “not merely with words but with…actions that we stand firmly behind Article V.”

Perhaps the new administration is realizing that if there is uncertainty about America’s commitment to Article V—if it is now conditional—the North Atlantic Treaty is worthless. If that’s the case, there’s no security for Europe. And if there’s no security in Europe, there’s no security for America. Trump must reinforce America’s—and his administration’s—commitment to Article V and NATO by delivering a speech focused on the importance of both.

“For the first time in history, there exists in peace an integrated international force whose object is to maintain peace through strength,” President Harry Truman explained when NATO was young. “We devoutly pray that our present course of action will succeed and maintain peace without war.” As Putin probes the West for weaknesses, as NATO ponders its future, as Trump tweets and deletes his way into an avoidable crisis, that prayer seems especially apt today.

Alan W. Dowd is a senior fellow with the Sagamore Institute Center for America’s Purpose. A version of this essay appeared in Providence.

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