MARACAIBO, Venezuela — At the hometown headquarters of presidential candidate Manuel Rosales, a campaign worker sounded more like a therapist as she comforted callers distraught over his crushing electoral loss to President Hugo Chavez.“Sir, I know, we all feel the same. But it’s not the end of the world. Stay strong,” said the aide, press adviser Alvara Valderrama, as she hung up the phone, her voice hoarse from taking dozens of calls.

Around Valderrama, volunteers took down posters of the smiling candidate and others swept up. One young man leaned against a wall, tears streaming from beneath his sunglasses.

The scene reflected the dejection and internal debate haunting the opposition after yet another failure to dislodge the popular Chavez, who cruised to his fourth success at the ballot box on Sunday with nearly 63 percent of the vote. With Chavez and his allies firmly in control of all levels of government, the prospects for a cohesive opposition are unclear.

But Rosales and other Chavez foes said their campaign built momentum and laid the foundation for a protracted political struggle against the government and — perhaps most important — for an opposition unified behind a single leader.

“This is a political triumph in the middle of an electoral setback,” Rosales said yesterday at his first post-election news conference.

“Manuel had a campaign of only about three months, and that was not enough time, but still he went from three percent or four percent support to 40 percent in the vote, and next time we will begin from that 40 percent,” said Henry Fuenmayor, executive secretary of Rosales’ campaign in Maracaibo.

“The results of Sunday’s elections show that Manuel will continue as the undisputed leader of the opposition.”

In an intense campaign after he was named the opposition’s consensus candidate in August, Rosales, the governor of the western state of Zulia, galvanized a fractured movement that had been dormant since its sound defeat in a 2004 recall referendum.

Opposition leader Teodoro Petkoff, who early in the race withdrew his own presidential bid to back Rosales, expressed optimism that competing factions within the anti-Chavez movement will be able to maintain that cohesion through Chavez’s new six-year term.

“The opposition is no less fractured than the government,” Petkoff said, referring to divisions among the ranks of the Chavistas, including between military and civilian leaders, and radical and moderate wings.

But Chavez claimed his victory gave him a strong mandate for a more radical turn toward socialism in his six-year term, and he has proposed constitutional changes that could abolish presidential term limits — allowing him to run again in 2012.

In Maracaibo, where on election night the streets ran red with the shirts and flags of celebrating Chavistas, the president’s supporters gloated over that possibility. One wore a T-shirt emblazoned with the slogan: “Chavez until 2012 ... for now.”

Rosales pledged to fight that bid with a proposal instead to reduce terms to four years.

He said he would welcome a meeting with Chavez, adding that “Venezuela is demanding for us not to continue living as enemies.”

In conceding defeat, Rosales said he planned to lead a renewed movement to resist such efforts democratically. Some Venezuelans praised the concession as a healthy step toward a limited rapprochement between deeply divided political camps.

But a few of his supporters also cried out “coward” and booed him when he conceded the race in Caracas. Some opposition supporters have complained of alleged vote irregularities, though opposition leaders and international observers signed off on the results.

Rosales yesterday emphatically pronounced the vote clean and challenged anyone to produce evidence to the contrary.

“The country spoke and the people spoke,” he said. “There is no place for making up lies. I’d be ashamed to lie to the Venezuelan people to justify an electoral defeat, I would never do it.”

Chavez said Rosales had acted responsibly by accepting defeat.

“I know there was pressure on him, to contest the result,” Chavez said. “He was capable of resisting the pressures.”