He came, he saw, he humbled himself. Never before has the president of America gone out of his way to pay tribute to a gathering of dissidents. The most powerful man on earth acknowledged that these otherwise powerless individuals from five continents possess what he rightly called “an even greater power — the power of conscience.”

What had brought President Bush to make this pilgrimage to Prague, en route to the G-8 summit? The answer echoed through the noble vision outlined in his speech — a speech that several seasoned observers of presidential oratory who attended the conference judged to be among the best that Mr. Bush has ever given.

This man, beset by his foes and abandoned by friends, still cares passionately about the love of liberty that inspires men and women to extraordinary self-sacrifice, even if the vision he set out in his second inaugural speech is as far from reality as ever. At one point, he made a wry reference to his own isolation, both among the leaders of the free world, and even within his own administration. Former chairman of the defense policy board advisory committee to George W. Bush, Richard Perle, had earlier reminded us that the president was “coming here to meet with his fellow dissidents.” “If standing up for liberty makes me a dissident,” Mr. Bush said, “I wear that title with pride.”

He recalled the chilling history of the Czerny Palace, the Czech Foreign Ministry, where the conference was taking place. It was there, in 1948, that foreign minister, Jan Masaryk, the son of the founding father of Czechoslovakia, Thomas Masaryk, was found dead in the courtyard while the communists mounted a “shameful coup” that snuffed out this fragile democracy. And it was there that the Warsaw Pact, the instrument of Soviet tyranny, was dissolved four decades later.

Mr. Bush not only reaffirmed America’s commitment to the advancement of freedom, but endorsed the Prague Document drawn up by two great former dissidents, Natan Sharansky and Vaclav Havel, who, together with the former prime minister of Spain, José Maria Aznar, had organized this gathering.

The Prague Document is addressed to the governments of the free world. It is an ambitious 10-point program calling on them not to leave dissidents to their fate. President Bush specifically promised to demand the immediate and unconditional release of non-violent political prisoners, and to instruct every U.S. ambassador to seek out dissidents living under nondemocratic regimes and ensure that they are not forgotten.

It is easy, of course, to sign up to declarations of intent, and harder to follow through with them. But Mr. Bush did not shy away from grasping the nettle of repression in China and Russia. To his critics in Europe, he reminded them that making freedom possible for those who lack it is “hard work,” and that the unspeakable violence of our enemies is simply “evidence that we are at war and that free nations must do what it takes to prevail.”

Mr. Bush was not the only envoy from the land of liberty to make the pilgrimage to Prague. Senator Lieberman — a man who knows something about dissent —spoke about the war on terror as a war for liberty. “Iraq,” he said, “is about the survival and success of the idea of freedom.” He encouraged the dissidents to keep going: “Every one of you has the power to change history. There is no such thing as a benign dictatorship.”

One center of attention at the conference was the Russian opposition leader, Garry Kasparov. His message was simple: “We do not ask for help. We ask the free world to stop providing Putin with democratic credentials.” He praised the chancellor of Germany, Angela Merkel, for criticizing the president of Russia to his face over the suppression of a demonstration by the group Mr. Kasparov leads, the Other Russia.

I asked Mr. Kasparov whether he feared assassination: “Nobody is safe,” he said. Him too? “Yeah, me too.” But he does not believe in a new Cold War: “The Iron Curtain cannot be restored.”

Mr. Kasparov expects a big crisis over the succession to Mr. Putin, but he refuses to say whether he will run for the presidency himself. He will be happy if he can hold protest rallies in St. Petersburg and Moscow next week — and if he is still a free man by the time elections are held next year.

Among the most impressive dissidents in Prague were those from Islamic countries, including Iran, Saudi Arabia, Egypt, Sudan, and the Palestinian Authority. I was struck by their courage in a cause that often appears hopeless to outsiders. If Muslims are given democracy, they do not have to dig its grave by electing its enemies, such as Hamas or the Muslim Brotherhood. They heard it straight from President Bush: “Freedom can be resisted and delayed, but not denied … Freedom is timeless. It is the right of every person and every nation in every age.” If these good men and women believe that liberty is not just a dream for their peoples, who are we to gainsay them?