Enrique Peña Nieto returned his once autocratic political party to power on Saturday and became the new president of Mexico, saying is was time for his country to assume its rightful and more elevated place in the world.

He envisioned the day when a more prosperous, peaceful Mexico would end hunger and business monopolies, and an expanding middle class would board high-speed trains that his government would build to take them to a better future.

A future with more broadband, he said.

And two more TV channels. And pensions. And a competitive booming economy that would make the country “the magnificent place it deserves to be.”

“This is the moment for Mexico,” Peña Nieto said in his first speech as president, before an audience of dignitaries gathered in the courtyard of the National Palace. Representing the United States was Vice President Biden.

As Mexico’s new president prepares to take office, The Post’s Mexico bureau chief William Booth talks about what Enrique Peña Nieto’s administration might mean for Mexico and the U.S. (The Fold/The Washington Post)

Before and after his remarks, hundreds of young people clashed with police at barricades around the historic center of Mexico City. The protesters threw rocks and molotov cocktails, smashed shop windows and street lamps, and tried to overturn a bus. Police fired tear gas to disperse the protesters. Several dozen people were injured.

In his remarks, Peña Nieto set forth an ambitious agenda of reform. He got his biggest applause when he vowed that public school teachers would no longer inherit their jobs but must be tested to prove their competence.

Mexico has some of the lowest education levels in the developed world, and many critics say one reason is the enormous power of the teachers union, the largest syndicate in Latin America, run by bullies who guard their wealth and clout at the expenses of Mexico’s kids.

The 46-year-old lawyer and career politician represents the new face of the old Institutional Revolutionary Party, or PRI, which ran Mexico for more than 70 years with a combination of coercion and corruption, until it was tossed from power in 2000.

Peña Nieto sought to allay fears and raise hopes. “There is an historic opportunity to convert Mexico into the great power it should be,” he said. “I will respect all the voices in the republic. I will ask your opinion, I will listen to the citizens, and I believe good proposals will guide this administration.”

He said his first goal was to reduce the violence that has plagued Mexico during outgoing President Felipe Calderon’s fight against organized crime.

“The state has lost ground in important areas. Lawlessness and violence have robbed various parts of the country of peace and freedom,” Peña Nieto said. “My government's first aim will be to bring peace to Mexico.”

But amid his soaring rhetoric was some straight talk. “We are a country where the few have everything and a majority lack rights,” he said. “Many Mexicans live day by day, worried they do not have a job, or that the corn is not growing in their fields. This is the Mexico we have to transform.”

Peña Nieto promised to focus as much on the victims as on the criminals. “Behind every crime is a story of sadness,” he said. “I want do something for victims and their families.” He said recently passed laws to help them are a good start but there is room for improvement.

He conceded that the criminal justice system is a mess, with dozens of competing criminal statutes. He said he would seek a constitutional amendment to write a unified criminal code, one that could begin to end decades of impunity and lackluster, poorly managed prosecutions.

The transfer of power, from Calderon and his National Action Party, to Peña Nieto and the PRI was rich with all the totems of power. At the stroke of midnight, in a somber, almost private ceremony, attended an small elite military unit in the Courtyard of Honor at the National Palace, Calderon gave Peña Nieto control of the country.

On Saturday at the Mexican Congress, Calderon removed the green, white and red sash of office and passed it to Peña Nieto. Later in the day, Peña Nieto went to the military parade grounds to formally take control of the country’s armed forces.