WASHINGTON — Tom Perez fought hard three years ago to win confirmation as U.S. labor secretary from a hesitant Senate. But lately he has been answering to another, unofficial title almost as frequently.
"Potentially our next vice president," a union official roared into a microphone as the Marylander took a stage recently on Capitol Hill.
With the primaries over and attention now focused on the general election in November, talk of Perez joining presumptive presidential nominee Hillary Clinton on the Democratic ticket has persisted, even as other names have come and gone.
The idea has drawn praise from labor and unease from some business groups.
Perez, a former head of the Maryland Department of Labor, Licensing and Regulation, has tried to tamp down talk about his future while overseeing one of the most active Labor Departments in a generation — thrusting an often-overlooked Cabinet position into the spotlight. In the waning months of the Obama administration, Perez has emerged as one of its most active officials.
His efforts at Labor, and his previous work as head of the civil rights division at the Justice Department, have caught the attention of fellow Democrats.
"Hillary, in my view, needs somebody who's passionate and gets out there and rallies folks," said Tony Coelho, the former California congressman who chaired Al Gore's 2000 presidential campaign. "Tom's not afraid to do what needs to be done."
But the prospect of Perez ascending to the second-highest office in the land has caused anxiety among business leaders, many of whom feel that his Labor Department has been overzealous.
"If you listen to him, he's done a great job," said Michael J. Lotito, co-chair of the Workplace Policy Institute of the management law firm Littler Mendelson. "I think if you ask businesses, they might tell you that while he was very good at holding listening sessions, he didn't listen very well."
If Perez were nominated and elected vice president, or offered a high-profile Cabinet post such as attorney general, it would eliminate one more potential candidate for statewide office in Maryland. Perez was talked about for the seat left by retiring Sen. Barbara A. Mikulski — he ultimately passed — and is considered a potential gubernatorial candidate in 2018.
The only vice president from Maryland, Spiro T. Agnew, catapulted to the job in 1969, only seven years after being elected Baltimore county executive. In 1973, amid a corruption scandal, he became only the second vice president in the nation's history to resign.
Perez endorsed Clinton in December and has been a visible surrogate, stumping this year in Wisconsin, Nevada, Virginia and elsewhere.
The political work could help the 54-year-old attorney raise his profile. Others believed to be on Clinton's short list — especially Sen. Elizabeth A. Warren of Massachusetts — are better-known figures.
But it is Perez's effort at the Labor Department that has bolstered his standing with the liberal Warren wing of the party — a constituency that Clinton will have to consider when weighing running mates.
At a time of gridlock in Washington, the department recently announced a regulation to extend overtime pay to millions of Americans. It is developing a rule to require financial advisers to operate in their clients' interests. And it has finalized a regulation that forces companies to disclose how much they spend on consultants to counter employee organizing efforts.
Supporters say it is a coincidence that the burst of activity has come in an election year. Some of the regulations now crossing the finish line have been in the works since before Perez took over in 2013.
But the timing doesn't hurt.
Mary Kay Henry, president of the 2 million member Service Employees International Union, offers the kind of praise for Perez's tenure that has become common among labor officials.
"He's been the most important labor secretary for working people since Frances Perkins," Henry said.
Perkins, who served under Franklin D. Roosevelt, is remembered as an architect of the New Deal. Perez keeps her portrait behind his desk at the Labor Department and has half-jokingly referred to the picture as a "brooding omnipresence in my office, asking me the question all the time: 'What's the right thing to do?'"
Perez, a Buffalo native who attended Harvard Law School and now lives in Takoma Park, is among the most liberal members of President Barack Obama's administration. Republican senators who had accused him of being overly political at the Justice Department opposed his confirmation as labor secretary.
Business groups are wary of the scope of new rules and regulations he has ushered in.
"He has pushed an ideological agenda that's hurt workers and employers," said Heather Greenaway of the conservative Workforce Fairness Institute in Washington. "It's almost like he was the fox guarding the henhouse, and now he could be in charge of the whole farm."
Perez played a central role in brokering an end to the strike at Verizon last month that involved nearly 40,000 workers. He brought company officials and the Communications Workers of America back to the negotiating table and opened the Labor Department building to both sides as a neutral space to continue talks.
Days after he intervened, the sides struck a deal.
George Kohl, a senior director for the Communication Workers of America, said he doubts Perez could have accomplished that if he were not viewed as an honest broker by company officials.
"He's unabashedly behind the things that he's doing, but I think he does them in a way that's open and honest and direct and engaging," Kohl said.
A spokesman for Verizon declined to comment.
Like Warren, Perez is popular with liberals and could help bridge the divide between Clinton and Democrats who backed Sen. Bernie Sanders, the Vermont independent who mounted an unexpectedly strong challenge for the nomination.
The son of Dominican immigrants, Perez could also serve as a counterweight to presumptive Republican presidential nominee Donald Trump on immigration — particularly in battleground states such as Florida, Colorado and Nevada, where large numbers of Hispanics turn out to vote.
The Clinton campaign has repeatedly turned to Perez as a surrogate to Spanish-language media.
And he has frequently been called on to deliver a fiery stump speech heavy on populist, middle-class rhetoric to a wider audience.
"We still have too many people who are stuck in the ditch, too many people who are working hard but falling behind," Perez told an audience this month in a riff ready-made for the campaign trail. "They motivate me to get out here and make sure we're swinging a bat on behalf of working families every single day."
Perez declined to be interviewed for this article.
Geography could work against his vice presidential prospects. He comes from a state that Democrats are already likely to carry in November, and so he would not offer his party an advantage in a swing state. But geography has not been a factor in vice presidential calculations in years. Vice President Joe Biden is from Delaware, a similarly blue state.
A bigger challenge for Perez, some say, is that few people outside Washington have heard of him. That could be a benefit in an anti-establishment election year, but it might make it harder for him to rally Democratic voters.
Perez's only stint in elected office was a single term on the Montgomery County Council, from 2002 to 2005. He was the first Latino to serve on the body.
Joel K. Goldstein, a professor at the Saint Louis University School of Law, studies the vice presidency.
"The formidable challenges he faces come from the facts that he's only been in the Cabinet for not quite three years, he hasn't held elected office other than at the local level and he has yet to demonstrate a national security credential," Goldstein said.
Other Marylanders have also been the subject of rumors for a spot on the ticket, or in a Clinton administration. Baltimore Rep. Elijah E. Cummings came up in some reports this year, but less so recently. Some have suggested former Gov. Martin O'Malley, but it is not clear that he has repaired his relationship with Clinton after his unsuccessful run against her for the nomination.
Ben Carson, the retired Johns Hopkins neurosurgeon who ran for the Republican presidential nomination this year, was briefly considered by some a potential running mate for Trump. He was then part of an effort to vet GOP vice presidential candidates but was dropped after he publicly suggested that Trump might consider a Democrat for the spot.
Perez is considered close to Obama, who once said that Perez's life story "reminds us of this country's promise."
His father, a doctor, died of a heart attack when Perez was 12 years old. He put himself through college with scholarships and jobs as a trash collector and as a warehouseman.
Perez launched a run for Maryland attorney general in 2006, but was knocked off the ballot by the state's Court of Appeals, which held that he lacked the 10 years of legal experience in Maryland required by the state Constitution. Douglas F. Gansler was elected to the post instead.
O'Malley chose Perez to serve as the state's labor secretary, a job he held from 2007 until 2009, when he took over the civil rights division at the Justice Department.
Rep. Chris Van Hollen, a Montgomery County Democrat now running for the Senate, said Perez was active on the council in opposing predatory lending and addressing prescription drug costs.
And there are other issues that have a direct link to his current role: He was subpoenaed in 2004 by Comcast for supporting an employee fired by the cable giant for trying to unionize about 300 employees.
Comcast ultimately dropped the case and rehired the employee.
"There's a consistency to his work from the council to where he is now," Van Hollen said. "He's very bright, he knows the issues and he combines that with an ability to connect with people."
Thomas E. Perez
Title: U.S. secretary of labor since 2013
Past: Montgomery County Council, 2002-2005; secretary of the Maryland Department of Labor, Licensing and Regulation, 2007-2009; assistant U.S. attorney general, 2009-2013.
Personal: Married, three children.
Education: Brown University, 1983; Harvard Law School, 1987; John F. Kennedy School of Government, Harvard University, 1987.