“I'm not saying it was a mistake to make immigration not just the central but almost the only topic” of the relationship with the United States, Calderón said at a White House news conference near the end of a two-day visit.

But without mentioning Fox, Calderón distanced himself from Fox's long and highly publicized insistence that the United States adopt sweeping reforms to benefit millions of Mexicans living in this country illegally and millions more who want to come.

“I have no interest in predicting or assuring that there will be powerful steps or great accomplishments,” said Calderón, who briefly served under Fox as secretary of energy. “I don't discard the possibility that they will happen. But I prefer to announce them after they have been accomplished.”

While Fox's impassioned crusade drew praise in a country whose immigrants had grown accustomed to governmental indifference, it ultimately led to frustration and disillusionment when Mexican hopes crashed against the realities of U.S. immigration politics.

Calderón's dance card for the whirlwind visit included meetings with Bush, Secretary of State Condoleezza Rice, Homeland Security Secretary Michael Chertoff and World Bank President Paul Wolfowitz. Calderón had informal chats with former Secretary of State Henry Kissinger and former Federal Reserve Chairman Alan Greenspan.

Calderón appeared relaxed and confident and seemed to have no illusions about the challenges awaiting him as he prepares for his six-year presidential term.

During his meeting with Bush, Calderón said he spoke of Mexico's frustration with a U.S. law authorizing the construction of 700 miles of fencing along the border. Bush's signing of the legislation last month dominated the news in Mexico, with critics saying he had betrayed his commitments to Fox and the spirit of the North American Free Trade Agreement. Many Mexicans believe NAFTA's openness to the free movement of goods and capital must be matched by an equally free movement of workers.

“I expressed our point of view that (the fencing) is not and cannot be a solution to the problem,” Calderón said.

He added that Bush said the fences were part of a strategy to address security concerns while setting the stage for comprehensive legislation that would legalize millions of illegal immigrants and allow more guest workers to enter the United States. Bush has said he hopes Congress, which the Democrats captured in Tuesday's midterm election, will work with him on the legislation.

“I assured the president-elect that the words I said . . . about a comprehensive immigration vision are words I still believe strongly,” Bush said while posing for pictures with Calderón in the Oval Office.

At his news conference, Calderón repeated a call for investment in Mexico that he had made a day earlier in a speech to leaders of Latino organizations. He said Mexicans' flight from their homeland can be contained only if they can find good-paying work south of the U.S. border.

“One kilometer of highway in Michoacan or Zacatecas can do more to solve the immigration problem than 10 kilometers of wall in Texas or Arizona,” Calderón said.

Jeffrey Davidow, former U.S. ambassador to Mexico, said Calderón is highly regarded in diplomatic circles for his ability to size up problems and fashion solutions. “I think he understands the United States,” Davidow said, noting that Calderón studied at Harvard and worked with U.S. lawmakers when he was a member of the Mexican Congress.

He said Calderón wants to ensure that Mexican-U.S. relations, which require cooperation on fronts from trade to combating organized crime, are not stalled by one party's frustration with the other.

“The U.S. and Mexico . . . fell into the habit of reducing their complex relationship to one issue at a time,” said Davidow, president of the Institute of the Americas in La Jolla. “In the 1990s, the U.S. reduced it to narcotics. Then Fox reduced it to migration. Both of those issues are too complex for easy fixes, and they ended up souring the rest of the relationship.”

Calderón also faces a list of domestic challenges. He declared that he is committed to fighting the brutal economic inequalities that animated his leftist rival's presidential campaign ahead of July's elections, which Calderón won with a margin so slight that it fueled cries of fraud and months of protests.

Andrés Manuel López Obrador has refused to recognize the victory and has announced that he will conduct his own inauguration ceremony Nov. 20 to take control of a parallel Mexican government he is forming.

Calderón also faces a growing threat from drug traffickers whose turf fights have thrown entire states and large portions of the border into turmoil.

Many Mexicans, as well as officials in the U.S. State Department, fear the creeping “Colombianization” of the country, in which drug bosses have become so powerful, bold and violent that they are corrupting entire police forces and judicial systems, destroying public confidence and stifling potential investment in legitimate business.

“He knows it is imperative that Mexican citizens feel that they are safe in their own streets,” said George Grayson, a Mexico expert at The College of William & Mary in Virginia, who was one of those invited to meet with Calderón.

“I am optimistic about Calderón,” Grayson said. “He's very bright and perceptive and pragmatic. I think he's a breath of fresh air.”