East German citizens celebrate after the border was opened on November 9, 1989. Reuters

Even before he left for Europe, Donald Trump had started with the demands and acrimony he brought with him to this week’s NATO summit. So right beforehand, Donald Tusk, the president of the European Council, pushed back. He urged America to appreciate its allies, pointing out that America didn’t have that many. Trump’s tone at the summit indicated he was more interested in hectoring them about military spending. But Tusk’s own biography shows exactly why the alliance is about so much more than defense budgets.

Tusk got his political start in the 1980s as an activist in Poland’s democratic dissident movement and in Solidarity. That was no game during communist times in Poland: Tusk and his fellow democratic activists were risking their own freedom in order to make their country free.

In the Cold War years, American and other NATO troops held the line in Europe, containing Soviet power. In the end, America won the Cold War. But it didn’t win by itself, through military power alone. It won because American and NATO military strength helped create the space for democratic dissidents in Eastern Europe—people like Donald Tusk and his associates—to gather a different kind of strength.

It was Polish dissidents and Polish workers like Lech Walesa, Solidarity’s leader, and others throughout the Baltics and Central Europe that brought down communist rule from within. They were inspired by the example of Western values and democracy. Many were also inspired by President Ronald Reagan, who spoke in the name of these values, which he believed should extend to all of Europe, not just Western Europe. Even more were inspired by the Polish Pope, John Paul II, who urged the people of Poland to “be not afraid.”

This history is important to remember at a time when the leader of the Western alliance seems determined to reduce it to a monetary transaction. During the Cold War, America had allies in unlikely places like Gdansk, Warsaw, Budapest, Vilnius, and Prague. These allies came through. The dissidents and workers didn’t contribute anything to military spending; at the time, their countries were in the Warsaw Pact, the other side, but their contribution to the common success was decisive, and equal to America’s own.

Donald Tusk went from being a dissident to being prime minister of Poland, and then to becoming president of the European Council—an institution of an undivided, democratic Europe. Poland went from being a poor, Soviet-occupied country to one that was relatively wealthy and free.

That good story—a miracle, actually—is replicated throughout Central Europe, and it is a testament to the success of what was then, and had been before, America’s grand strategy. America pursued, from President Woodrow Wilson through Presidents Franklin D. Roosevelt, Harry Truman, John F. Kennedy, and Reagan, a course reflecting the understanding that the advance of American interests was linked to the advance of American values.

America did not fight the Cold War for itself alone, but for the democratic world, the free world—and those who wished to join it. It did so not out of abstract charity, but because generations of Americans understood the linkage of interests and values. They also understood, through bad experience, that the failure of those values would lead to bad real-world outcomes, like the Second World War. The American grand strategy, developed the hard way through two world wars and executed after 1945, gave America and the rest of the West two generations of peace and unprecedented prosperity. First America helped Western Europe find peace, security, and prosperity. Then America and its partners helped extend that peace to almost all of Europe. And millions of people, Europeans and Americans, came out of this ahead.

Meanwhile, though, the world remains a dangerous place. Allies help America deal with those dangers.

America needed its allies after it was attacked on 9/11, and its allies came through. Soldiers from NATO and non-NATO countries—British, Canadian, French, German, Australian, Georgian, and many others—have fought in Afghanistan, in solidarity with us. Many have died doing so. The lives of 455 Britons, 158 Canadians, 86 French, and 54 Germans mean something to families who have given their loved ones in solidarity with America.

America may need them again. President Trump would do well to remember that.

On July 11, NATO leaders, including Trump, reached agreement on a Summit Declaration that affirms NATO solidarity and the rules-based international order, and urges efforts to thwart Russian aggression. It also calls on NATO allies to respect the alliance’s agreed goal of spending 2 percent of GDP on defense. It’s a good thing that this declaration was agreed on, and that the United States did not withhold or withdraw consensus (as the president did after the G7 Summit in June).

Trump is right to push American allies to increase their defense spending. He is right to remind the NATO alliance that everyone must do their share. He is right to urge Germany to reconsider its plans to help Russia gain even more leverage over Europe through construction of a new natural-gas pipeline. He is right to want to fix economic and trade problems. Putting pressure on NATO, the European Union, and individual European governments to fix problems and meet commitments can be a good thing, and other presidents have done this as well.

But some of Trump’s rhetoric seems to suggest that the pressure is an excuse to undermine the West. Even if that is not the intent, he serves no good American interest by placing gratuitous strain on the alliance. Undermining the West has been the Kremlin’s game for a long time. It shouldn’t be America’s.

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