President Vicente Fox, facing deepening criticism of his administration, urged Mexicans on Wednesday not to "become disillusioned with democracy" during the transition away from the country's authoritarian past and vowed that "the best is yet to come."

Thousands of anti-Fox protesters jammed streets and virtually closed down much of the city center during the day, hours before the president spoke in an annual message before a joint session of Congress and a national television audience. Fox's speech was short on promises, modest in its claims of achievement and often sounded like a tutorial on democracy.

"Today our political life is more open, more plural and more intense than ever," said Fox, 62, whose historic election in 2000 ended 71 years of one-party rule in Mexico, during which presidents governed with vast powers. "Democracy is not the absence of conflict; it is the freedom to debate problems and the best way to solve them. . . . Democracy is Mexico's destiny."

Fox's speech was markedly different from his three previous state-of-the-nation addresses, in which his bold claims of success seemed at odds with the fact that he had been unable to persuade the opposition-dominated Congress to pass his important initiatives, such as those on energy, labor and tax reform. Commentators consistently said that Fox appeared out of touch with the widely held public view that he was not facing reality.

On Wednesday, Fox claimed important successes in areas such as poverty reduction and the arrests of thousands of drug traffickers and kidnappers. But his speech focused much more closely on what most analysts agree is his most important achievement: Mexico's undeniable shift toward more democratic freedoms during his administration.

"Thanks to a hard and prolonged struggle, now we can speak, decide, criticize, argue and participate, with the dignity of free men and women," said Fox, arguing that decision-making in a democratic society is often chaotic and messy. "Democracy's inherent problems are not cause for discouragement; they are a challenge. . . . Democracy's challenges can always be overcome with more democracy."

Fox acknowledged that in a new era of separation of powers, he and Congress had not worked well enough together, and he admitted that he had not reached many of his goals. But he said that because of his "democratic project," Mexicans have never had greater freedom of the press, transparency in government and elections or ability to participate in government decisions.

Outside, thousands of Mexicans disagreed, filling the streets to protest Fox's programs, including his farm and energy policies and a recent reform that requires many government workers to pay more of their own pension costs.

Fox's main obstacle was repeated interruption by opposition legislators who shouted him down and held up signs that said, "More Lies" and "Pinocchio." Political analyst Ana Maria Salazar said Fox was a "lame duck" and that the best he could hope for from his speech, and for the remainder of his six-year term, was to ensure that Mexicans "continue to believe in democracy."

"He has to protect the image that democracy is good for Mexico, and that while chaotic, it is still the future for Mexico," she said.