His relationship with Salinas, Pena Nieto said on CNN en Espanol this week, “is cordial, one of respect . . . and I have nothing more to say about it.”

Handlers have packaged Pena Nieto carefully, offering videos of him canoodling with his glamorous soap opera-star second wife in hopes of overcoming a few “deer in the headlights” gaffes that he made in media appearances last fall.

“They’ve been extremely careful of allowing him to be examined by journalists,” Mossige said. “He has the appearance of giving very canned answers.”

Even so, in recent weeks the PRI appears strong and cohesive amid predictions that it may capture not just the presidency but also one, and possibly both, chambers of Congress.

Pena Nieto, too, appears more at ease. Experts credit him with surrounding himself with intelligent advisers – more so than current President Felipe Calderon – and say those advisers may fill his Cabinet if the PRI returns to power. He’s also bucked some orthodoxy. In a very secular, anti-clerical party, he’s sought the blessing of Pope Benedict XVI. He’s also proposed opening the state oil company, Pemex, to private investment, touching on a nationalist pillar around which the PRI once rallied.

“The PRI is an extremely complex and sophisticated organization,” said George W. Grayson, a scholar on Mexico at the College of William & Mary in Williamsburg, Va.

“In Mexico today, it’s probably the broadest party,” echoed Shannon K. O’Neil, a political scientist at the Council on Foreign Relations, a research center. “You’ve got free-market people, you’ve got progressive nationalist types and everything in between.”

Any members of the PRI old guard who get the ear of a PRI president would find significant opposition to operating in a corrupt way.

“Congress matters. Governors matter. The press matters, and there’s an emerging civil society. All these things that weren’t independent through the 1990s are independent today,” O’Neil said.

If Pena Nieto wins by the wide margin that pollsters predict, his mandate is still unlikely to be a sweeping majority of Mexicans, and even Fox suggests that the country’s problems are so severe that voters should back the strongest horse.

Fox said the last three Mexican presidents, himself included, suffered weak mandates and faced “radical opposition” that led to “zero decisions for the country.

“The country cannot endure a fourth six-year period like this.”

Calderon came to office in 2006 with less than 36 percent of the vote and just slightly more than a half-percentage point margin over his fiery closest opponent, Lopez Obrador. When his all-out war against crime groups bogged down, he was unable to cut deals with the political opposition for needed political reforms.

“In Calderon’s DNA, there is a loathing of the PRI. Calderon just views the PRI as toxic,” Grayson said. “He really couldn’t get legislation through Congress because of his weak, inexperienced team and his profound distrust of the PRI.”