Mexico's new president, Felipe Calderon, begins his first full work week Monday with an ambitious agenda and many challenges. Opposition leaders continue to deride him as an illegitimate president and many of the nation's most powerful interests are opposed to some of his key reform plans. VOA's Greg Flakus reports from Mexico City.

The celebrations are over and so are most of the protests, at least for the moment, and now President Calderon must begin his effort to pull the country together and advance programs that he believes will benefit all Mexicans.

In his inaugural address Friday, Mr. Calderon said that politics is all about cooperation between parties, powers and citizens to improve the life of the people. He also called for dialogue with his opponents, but they have not responded in kind.

Carlos Navarrette, leader of the leftist Party of the Democratic Revolution, continues to call Mr. Calderon an illegitimate president.

He says Mr. Calderon's National Action Party, or PAN, is a minority in Congress, he was elected by a minority and his electoral win is still disputed by a significant part of the population.

Mr. Calderon won the July 2 election by a razor thin margin and PRD candidate Andres Manuel Lopez Obrador challenged the result as fraudulent. The Federal Electoral Tribunal, however, found no evidence of fraud.

Lopez Obrador drew hundreds of thousands of demonstrators to the streets of Mexico City in the weeks after the election, but his most recent rallies have drawn only a few thousand. Public opinion polls show 85 percent of Mexicans accepting Mr. Calderon as the new president, but that has not silenced Lopez Obrador.

He continues to call on his supporters to, as he puts it, "rescue" Mexico. But in a significant shift of strategy, he now says he will no longer concentrate on attacking what he sees as a fraudulent election. On Saturday he told supporters they should now focus on advancing their cause, in Congress and elsewhere.

The main cause the losing candidate has championed is that of alleviating the poverty in which more than 40 percent of the population is trapped. But President Calderon has also addressed that problem by proposing a review of social programs and greater investment to spur job growth.

Mr. Calderon has called for a reduction of his own salary and those of other high officials and at a meeting with military leaders on Saturday, he proposed an increase in salaries and benefits for the armed forces, whom he has called on to help fight drug traffickers and other criminals who threaten the nation's stability and public order.

An important test for President Calderon will be how he handles relations with the party that controlled Mexico for more than 70 years until the election of Vicente Fox in the year 2000 - the Institutional Revolutionary Party, sometimes called the PRI.

Political analyst Ana Maria Salazar says the PRI sees an opportunity to regain some of the political ground it has lost by exploiting the bitter fight between the ruling party and the PRD.

"They are using the conflict between the PAN and the PRD as a way of gaining power and gaining status," said Ana Maria Salazar. "Every time the president needs something, a law to be passed, a political negotiation to resolve a conflict, they are going to have to sit down and talk with the PRI. And the PRI is going to be seeking to protect their interests, not only as a party, but their politicians and what they are going to ask for is going to be much more expensive than it would be if we were in a more normal situation."

So far there is no indication that the PRD or other leftist parties will engage in dialogue with President Calderon or the PAN members of Congress. PRD spokesmen say they will try to obstruct Mr. Calderon proposals and will not talk directly with the man they say gained power through fraud. In terms of sheer voting power, a PAN-PRI coalition would be able to sidestep the PRD, but President Calderon will likely have to negotiate with the PRI on each and every proposal to gain the former ruling party's support.