By Rebecca Adams, CQ Staff

Friction between workers and managers is one of the central dynamics of American life. And the Labor secretary’s job, in short, is to bridge the gap. He or she enforces wage, hour, workplace safety and anti-discrimination statutes; administers unemployment insurance and job training programs; regulates workplace pension, health and other benefits; and oversees the Occupational Safety and Health Administration and the Mine Safety and Health Administration.

For McCain

Randel K. Johnson, U.S. Chamber of Commerce vice president

He has overseen labor, employee benefits, education and immigration policy during his decade at the Chamber, the nation’s pre-eminent business advocacy group. McCain may be hesitant to put a business lobbyist in the position, but if he does, Johnson would be at the top of the list. A former counsel on labor issues at the House Education and Labor Committee, Johnson has been advising the campaign informally. Johnson himself downplays the possibility, but some other lobbyists say that his expertise, Capitol Hill connections and ties to McCain put him in the running. Johnson and the Chamber applauded McCain’s efforts to update the nation’s immigration laws and create a guest worker program for immigrants, an issue that cost McCain points with the party’s conservative base.

John Engler, National Association of Manufacturers president

He would be a reassuring presence at Labor for the nation’s business community. As president and chief executive of NAM since 2004, he has developed close and extensive ties to executives of manufacturing and other companies around the country. The governor of Michigan for a dozen years ending in early 2003, he asserts that his policies led to the creation of 800,000 jobs in one of the nation’s most economically troubled states during his tenure. Engler is not the most likely pick, however. His job at NAM is a comfortable fit. And McCain won the Michigan primary in 2000 without the help of Engler, who had promised to ensure that George W. Bush would carry Michigan.

Jim Talent, Former Missouri senator and congressman

An articulate proponent of the core conservative belief that more federal authority over domestic programs should be handed to the states, he sought refuge at the Heritage Foundation as a senior fellow after losing his Senate seat in 2006 by 2 percentage points to Democrat Claire McCaskill . That reduced his winning average to .333 in statewide races in one of the nation’s traditional bellwethers. He won the Senate seat by 1 percentage point in a 2002 special election, but two years before that he lost a governor’s race by 1 point. He also spent eight years in the House, including two terms as Small Business Committee chairman, and was an ardent advocate of moving more welfare recipients to the workforce, as was required in the 1996 welfare overhaul. Talent originally supported Mitt Romney for the GOP nomination but is now working to help McCain win Missouri.

For Obama

Linda Chavez-Thompson, former AFL-CIO executive vice president

She would be a logical choice if Obama decides he wants a veteran labor leader at the department. Before retiring last fall she spent a dozen years in the No. 2 post at the AFL-CIO, the first ethnic minority in so high a post. The post capped three decades moving up the ranks of the labor movement in right-to-work Texas, starting as a Laborers’ International Union secretary and including stints as head of the San Antonio and statewide American Federation of State, County and Municipal Employees. For the past 11 years she’s also been a vice chair of the Democratic National Committee.

Richard A. Gephardt,former House Democratic Leader

It would be a major coup to convince Gephardt to return to Washington, which he left after his second presidential run came up short in 2004. Now a highly compensated counsel at the global law firm DLA Piper and a consultant for Goldman Sachs, he’s said he’s out of government for good. A Teamster’s son, unions and their members have been Gephardt’s base of political support since his first election in 1976 to represent St. Louis in Congress. During 14 terms he pressed workers’ causes relentlessly, especially efforts to protect labor in international trade agreements. “It’s your fight, too,” was the populist slogan of the 1988 White House run he lost to Michael S. Dukakis, after which he moved up the party hierarchy and spent 13 years as floor leader.