LA PAZ - Bolivia's newly declared interim president, until now a second-tier lawmaker, faces the challenge of winning recognition, stabilizing the nation and organizing national elections within three months at a time of bloody political disputes that pushed the nation's first indigenous leader to fly off to self-exile in Mexico after 14 years in power.
Some people took to the streets cheering and waving national flags Tuesday night when Jeanine Anez, who had been second-vice president of the Senate, claimed the presidency after higher ranking successors to the had post resigned. But furious supporters of the ousted Evo Morales responded by trying to force their way to the Congress building in La Paz yelling, "She must quit!"
The constitution gives an interim president 90 days to organize an election, and Anez's still-disputed accession was an example of the problems she'll face.
Morales' backers, who hold a two-thirds majority in Congress, boycotted the session she had called to formalize her accession, preventing a quorum.
Frustrated in that effort, she took power in any case, with no one to swear her in, saying the constitution did not specifically require congressional approval.
"My commitment is to return democracy and tranquility to the country," she said. "They can never again steal our vote."
Bolivia's top constitutional court issued a statement late Tuesday laying out the legal justification for Anez taking the presidency - without mentioning her by name.
But other legal experts challenged the legal technicalities that led to her claiming the presidency from such a relatively low-ranking post, saying at least some of the steps required Congress to meet.
And the lingering question could affect her ability to govern.
"It doesn't seem likely" that Morales' party "will accept her as president. So the question of what happens next remains - still quite unclear and extremely worrying," said Jennifer Cyr, an associate professor of political science and Latin American studies at the University of Arizona.
Eduardo Gamarra, a Bolivian political scientist at Florida International University, argued that the constitution clearly states that Anez didn't need a congressional vote to assume the presidency. Even so, "The next two months are going to be extraordinarily difficult for President Anez," he said.
She will need to arrange formation of a new electoral court, find a non-partisan staff for the electoral tribunal and get Congress to vote on new election. All of it must be done before Jan. 22, when Morales' current term and everyone else's was meant to end. And all of it must be done while Morales' Movement for Socialism party still controls both houses of Congress.
Morales resigned Sunday following the weeks of violent protests fed by allegations of electoral fraud in the Oct. 20 election, which he claimed to have won.
Morales had accepted an Organization of American States audit reporting widespread irregularities in the vote count and calling for a new election.
But he stepped aside completely when Gen. Williams Kaliman, the armed forces commander, "suggested" he leave - a move that Morales and his backers branded a coup d'etat and his critics called a popular uprising.
Bolivia's first indigenous president arrived in Mexico on Tuesday under a grant of asylum and, just 60 years old, vowed to remain active in politics.
Although Anez met with Gen. Kaliman, it was uncertain how much support she could count on from other power centers.
She immediately tried to set herself apart from Morales. Wearing the presidential sash of office, she greeted supporters at an old presidential palace instead of the modern 26-story presidential office with a heliport that was built by Morales and that his foes had criticized as one of his excesses.
She also carried a Bible, which had been banned by Morales from the presidential palace after he reformed the constitution and recognized the Andean earth deity Pachamama instead of the Roman Catholic Church.
Morales said on Twitter from Mexico that Anez's "self-proclamation" was an affront to constitutional government. "Bolivia is suffering an assault on the power of the people," he wrote.
Even before Anez acted, thousands of his supporters were in the streets of the capital in peaceful demonstrations clamoring for his return. Military fighter jets flew repeatedly over La Paz in a show of force that infuriated Morales loyalists who were blocked by police and soldiers from marching to the main square.
"We're not afraid!" shouted demonstrators, who believe Morales' departure was a coup d'etat and an act of discrimination against Bolivia's indigenous communities.
"Evo was like a father to me. We had a voice, we had rights," said Maria Apasa, who like Morales is a member of the Aymara indigenous group.
Mexican Foreign Secretary Marcelo Ebrard said his country's diplomats had to scramble to arrange a flight path for the plane because some nations initially closed airspace to it. The plane stopped in Paraguay to refuel instead of Peru, as initially planned.
The one-time llama shepherd from the Bolivian highlands and former coca growers' union leader helped lift millions out poverty as president, increasing social rights and presiding over stability and high economic growth in South America's poorest country.
But even many supporters eventually grew weary of his long tenure in power - as well as his insistence in running for a fourth term despite a public referendum that upheld term limits, restrictions thrown out by a top court that critics contend was stacked in his favor.