Perhaps the most important remark in President Obama’s speech in Poland this week, marking the twenty-fifth anniversary of its democratic revolution, was the least noticed by commentators. “The victory of 1989,” Mr. Obama said, “was not inevitable.”

It is a truism, however, that does not seem to penetrate the thinking of the president himself or his closest foreign policy advisors. Poland’s daring break from communist tyranny was not only the result of amorphous “centuries of Polish struggle,” or the heroic resistance of the Warsaw uprising, or even the remarkable influence of Pope John Paul II. It was, in part, the result of American presidential leadership.

That leadership began, in a sense, on August 7, 1980, when an unemployed electrician named Lech Walesa climbed a perimeter fence in the Lenin Naval Shipyard in Gdansk to address his fellow workers. Walesa led them in an “occupation strike,” and over the next four days the workers barricaded themselves into the shipyard, locking out security forces. It was the beginning of the Solidarity movement.

Local managers tried to negotiate with them. The workers kept escalating their demands: they wanted free and independent trade unions, the easing of censorship, and the release of political prisoners. They pledged nonviolence. Talks continued through the day.

In one of the negotiating rooms, an unknown striker removed the bust of Vladymir Lenin, the ruthless architect of the Russian Revolution of 1917. The striker replace Lenin’s bust with a photograph, cut from a newspaper. Whose picture had been substituted for that of Lenin? President Jimmy Carter?

As political scientist Paul Kengor reminds us, it was a photograph of a U.S. presidential candidate: a man with a reputation as a fierce anti-communist who intended to reassert American power and its democratic ideals on the world stage. His name was Ronald Reagan.

Watching the events in Poland carefully, Reagan was deeply affected by the pope’s historic visit, argues Kengor in The Crusader: Ronald Reagan and the Fall of Communism. “He sensed the immensity of what had transpired,” he writes, “and recognized that this was a momentous event that threatened Communism’s hold on Eastern Europe.” As soon as Reagan came into office, he put the democratic struggle in Poland near the top of his foreign policy agenda of defeating Soviet Communism. “We can’t let this revolution against Communism fail without our offering a hand,” Reagan wrote in his diary at the time. “We may never have an opportunity like this in our lifetime.”

Reagan could express this hope because he believed firmly in American Exceptionalism: the idea that America’s successful experiment in self-government was a product of remarkable political wisdom, courage, and leadership–and that Providence had an interest in its continued success and influence on the world stage. “You and I have a rendezvous with destiny,” he said in 1964, at the height of the Cold War. “We’ll preserve for our children this, the last best hope of man on earth, or we’ll sentence them to take the last step into a thousand years of darkness.”

Thus, in December 1981, Reagan refused to allow the United States to remain on the sidelines when Polish Prime Minister Wojciech Jaruzelski launched “Operation Springtime,” sending tanks into Warsaw, declaring martial law, and rounding up thousands of Solidarity members in a single night. Reagan called Pope John Paul II on December 14 to seek ways to cooperate in the days following martial law. Reagan then addressed the American people directly about the crisis on December 23: “For a thousand years, Christmas has been celebrated in Poland, a land of deep religious faith, but this Christmas brings little joy to the courageous Polish people. They have been betrayed by their own government.”

The president asked all Americans to light a candle during the Christmas season in support of freedom in Poland. It was a powerful symbolic act, and it helped to make the struggle in Poland America’s struggle.

Next came some hard-nosed diplomacy. The same day of his December address to the American people, Reagan sent a note to Soviet leader Leonid Brezhnev:

“The recent events in Poland clearly are not an ‘internal matter,’ and in writing to you, as the head of the Soviet government, I am not misaddressing my communication. Your country has repeatedly intervened in Polish affairs during the months preceding the recent tragic events…Since Afghanistan, nothing has so outraged our public opinion as the pressures and threats which your government has exerted on Poland to stifle the stirrings of freedom.”

Brezhnev fired off a note complaining that it was the United States, not the Soviet Union, which was interfering in Polish affairs. Reagan followed up with another note: he proposed that the Polish people “only be given the right of self-determination that had been promised to them by Joseph Stalin himself at the Yalta Conference.”

Ronald Reagan, the passionate anti-communist since the 1940s, had been waiting to deliver a message like that to the Soviet Union for nearly forty years.

Now compare that to Mr. Obama’s policies in the Middle East, where the forces of freedom have looked in vain for American leadership. Before the “Arab Spring” that began in Tunisia, tens of thousands of Iranian demonstrators took to the streets of Tehran in the summer of 2009 to contest a rigged election. Nothing like it had occurred in Iran since its Islamic Revolution in 1979. Yet Mr. Obama, determined to avoid even the appearance of “meddling” in Iranian affairs, said nothing and did nothing. Then the bloodletting began, as the theocratic thugs in Tehran cracked down on the protestors. The president remained mostly mute–even as peaceful demonstrators by the thousands were arrested, tortured, raped, and executed.

Democratic protestors in Tehran carried signs saying: “Obama: are you with us or with the dictator?”

In those protests was the possibility of regime change, and the best chance for keeping the mullahs from acquiring nuclear weapons. Yet Barack Obama, lacking confidence in America’s moral leadership, remained a hapless spectator of events. The same could be said of his policies in Syria, Egypt, Libya, and elsewhere.

Reagan’s determination to help Poland’s freedom-fighters went beyond symbolism and diplomatic cables. He announced economic sanctions against Poland and the Soviet Union. The United States, along with Great Britain under Margaret Thatcher, delivered millions of dollars of covert assistance to Walesa and Solidarity, helping to keep the movement alive during the years of martial law.

Reagan was willing to exert American leadership, to act on his own if necessary, to support democratic resistance movements. He faced intense criticism, at home and abroad.

French President Francois Mitterrand insisted that Polish society was not becoming more “liberal,” and that nothing would come of the democratic movement in Poland. West German Chancellor Helmut Schmidt told Secretary of State Alexander Haig that it was absurd for Reagan to think that he could overthrow the post-World War II division of Europe. “The West needs to be realistic regarding the possibilities for change in Eastern Europe,” he said. George Kennan, one of the architects of America’s containment policy, claimed that Poland’s demand for freedom was “inevitably self-defeating” and that Reagan was sabotaging détente.

Well, we all know the rest of the story.

Former Polish president and Nobel Laureate Lech Walesa unveiled a statue of Ronald Reagan in Warsaw in November 2011, honoring the late U.S. president for inspiring Poland’s fight against communism. “I wonder whether today’s Poland, Europe and world could look the same without President Reagan. As a participant in those events, I must say that it’s inconceivable.”

It is also inconceivable that these great strides toward human freedom could have been accomplished without an American president convinced of the exceptional nature and mission of this democracy. No U.S. president has so openly repudiated this idea as Barack Obama. No president has expressed it–and embodied it–with greater power than Ronald Reagan.

Joseph Loconte is an associate professor of history at The King’s College in New York City and the author of God, Locke, and Liberty: The Struggle for Religious Freedom in the West (Lexington Press, 2014).