WASHINGTON — President Barack Obama nominated Assistant Attorney General Thomas Perez to be the next secretary of labor, choosing a Hispanic lawyer with experience in civil rights and workplace issues to his second-term Cabinet. Obama called Perez a consensus builder whose story “reminds us of this country’s promise.”

“Tom’s made protecting that promise for everybody the cause of his life,” Obama said in an appearance with Perez in the White House East Room Monday.

If confirmed by the Senate, Perez, who has been head of the Justice Department’s Civil Rights Division since 2009, would take over the Labor Department as Obama undertakes several worker-oriented initiatives, including an overhaul of immigration laws and an increase in the minimum wage.

Before taking the job as assistant attorney general, the 51-year-old Perez was secretary of Maryland’s Department of Labor, Licensing and Regulation, which enforces state consumer rights, workplace safety and wage and hour laws.

Perez’s nomination has been expected for weeks, and comes with vigorous support from labor unions and Latino and civil rights groups. Among those at the White House ceremony Monday were AFL-CIO President Richard Trumka and NAACP President and CEO Benjamin Jealous.

“At a time when our politics tilts so heavily toward corporations and the very wealthy, our country needs leaders like Tom Perez to champion the cause of ordinary working people,” Trumka said in a statement.

Perez also has Republican congressional critics who can be expected to oppose his confirmation. Sen. Jeff Sessions, R-Ala., called the nomination “unfortunate and needlessly divisive.”

In choosing Perez, the son of immigrants from the Dominican Republic, Obama would be nominating his first second-term Latino Cabinet member. Perez, a lawyer with a degree from Harvard Law School, would replace Hilda Solis, a former California congresswoman and the nation’s first Hispanic labor secretary.

At the Justice Department, Perez has played a leading role in the agency’s decision to challenge voter ID laws in Texas and South Carolina that could restrict minority voting rights. A federal court later struck down the Texas law and delayed implementation of the law in South Carolina until after the 2012 election.

Perez thanked Obama, interspersing some Spanish into his remarks.

“Our nation still faces critical economic challenges, and the department’s mission is as important as ever,” Perez said.

Citing his past work as a civil rights lawyer, a Senate aide and as a member of on the Montgomery County Council in Washington’s Maryland suburbs, Obama said: “Tom fought for a level playing field where hard work and responsibility are rewarded and working families can get ahead.”

But some GOP lawmakers have been critical. Sessions said Perez “has aggressively sought ways to allow the hiring of more illegal workers.”

Other Republicans have cited his role in persuading the city of St. Paul, Minn., to withdraw a lending discrimination lawsuit from the Supreme Court. In exchange, the Justice Department declined to join two whistle-blower lawsuits against St. Paul that could have returned millions in damages to the federal government.

The St. Paul case had challenged the use of statistics to prove race discrimination under the 1968 Fair Housing Act, and Justice Department officials were concerned the court could strike down the practice.

Moreover, a newly released report by the Justice Department’s inspector general is likely to provide more fodder for Republicans who say the Justice Department’s Civil Rights Division has been too politicized.

The report, released last week, said Perez gave incomplete testimony to the U.S. Commission on Civil Rights when he said the department’s political leadership was not involved in the decision to dismiss three of the four defendants in a lawsuit the Bush administration brought against the New Black Panther Party.

The report also concluded that Perez did not intentionally mislead the commission and that the department acted properly.

Republican Sen. Charles Grassley of Iowa said Perez appeared to be “woefully unprepared to answer questions” from the Civil Rights Commission.

Lynn Rhinehart, general counsel at the AFL-CIO, said the report shows that Perez, who was first hired by the civil rights division as a career attorney under President George H.W. Bush, restored integrity to the voting rights program at the Justice Department.

“The DOL becomes a back-burner agency without a secretary who knows how move workplace issues through the administration, the Hill and the business and labor communities,” said Steve Rosenthal, a longtime labor strategist and former associate deputy secretary of labor during the Clinton administration. “Those are difficult waters to navigate.  But Tom Perez is guy who can do it.”

Perez was confirmed by a vote of 72-22 when Obama nominated him for the Civil Rights Division job.

Carl Tobias, an expert on the confirmation process and the Justice Department, said Perez’ confirmation vote might be more difficult this time around because the Senate is more partisan, it is Obama’s second term and the job is for a Cabinet level.

“Heading CRD means that he had to address many difficult, contentious issues,” said Tobias, a professor at the University of Richmond School of Law.