WASHINGTON – Ron Kirk emerged late Wednesday as the front-runner for an Obama Cabinet post handling international trade, thrusting the pro-trade former Dallas mayor into a sensitive balancing act between unions and business interests.

High-level Democrats confirmed that Mr. Kirk is a leading contender for U.S. trade representative, and there were reports his nomination would be announced as early as Friday. Reached by phone, Mr. Kirk declined to comment.

Talk about him in the job was "more prevalent today and a little bit more emphatic," said John Murphy, vice president for international affairs at the U.S. Chamber of Commerce. He added that Mr. Kirk isn't well-known nationally but seemed to have a "heartening" record of support for free trade and its benefits in Texas.

"Trade has been one of the only bright spots for the U.S. economy, and the Obama team is going to need every tool in its tool box," he said.

The trade representative is an ambassador-level post with a staff of more than 200 and offices in Washington, Geneva and Brussels. Since the Ford administration, it has come with Cabinet rank.

If confirmed by the Senate, Mr. Kirk would probably spend much of his time overseas hammering out trade deals and persuading foreign leaders to drop trade barriers, curb movie piracy, and open new markets for U.S. goods.

Leaders of organized labor, a key ally in Mr. Obama's victory last month, are anxious about the trade appointment. Some aren't sure what to make of Mr. Kirk.

"The jury's out," said Becky Moeller, president of the Texas AFL-CIO.

As mayor from 1995 to 2001, Mr. Kirk touted free trade. In a series of overseas trips, he pitched the Dallas area as an ideal trading partner.

The top Republican on the Senate panel that will confirm the next trade representative, Iowa Sen. Charles Grassley, questioned Mr. Kirk's qualifications. Aides noted that while most of Mr. Obama's Cabinet picks have deep experience in their fields, Mr. Kirk has little background on trade issues.

Mr. Kirk, 54, was the city's first black mayor. He helped win approval for two controversial projects, the Trinity River overhaul and American Airlines Center, and was considered an ally of business interests.

He ran for the Senate in 2002 but lost to Republican John Cornyn. Since, he's been a lawyer and lobbyist, and this year, he was a surrogate campaigner for Mr. Obama, traveling to other states and helping to introduce the candidate at a big Reunion Arena rally.

Mr. Kirk was also considered for transportation secretary, but that job reportedly is going to retiring GOP Rep. Ray LaHood of Illinois, and Mr. Kirk had told friends he preferred the trade post.

Trade sits at the intersection of foreign relations and domestic economic policy. With debates over financial bailouts and stimulus packages looming in Congress, many say trade talks won't be front-and-center for Mr. Obama.

Three trade deals are pending in Congress. Mr. Obama opposes a pact with Colombia, echoing U.S. unions' complaints about anti-labor violence. A South Korea pact is stalled amid fears for the U.S. auto industry. A deal with Panama is considered less controversial.

The next trade representative would face stalled World Trade Organization talks known as the Doha Round, and would be charged with confronting China and others on export subsidies, tariffs and copyright issues, and fighting to keep markets open to U.S. goods.

"There are a lot of opportunities," said William Krist at the Woodrow Wilson Center.

Mr. Krist wasn't familiar with Mr. Kirk, but said the next trade representative's work could be critical: "Any time that you have a lot of economic problems, there's a real tendency for a growth of trade protectionism, and that could be a disaster for the world economy."

Frank Vargo, vice president for international economic affairs at the National Association of Manufacturers, likewise said he wasn't familiar with Mr. Kirk but said Mr. Obama has lined up an "impressive" Cabinet, and an appointment to the Cabinet implies that Mr. Kirk would have his trust.

"Being mayor [in] a border state, certainly he's going to be familiar with the benefits of trade, particularly NAFTA, which has benefited Texas a lot," he said.

And he predicted that as Mr. Obama wrestles with the economy and foreign relations, "trade will inevitably become a priority."

Mr. Kirk's chances for the job got a boost Tuesday when the top contender, Rep. Xavier Becerra of Los Angeles, said he would stay in Congress.

Mr. Obama reportedly offered the Californian the job two weeks ago. But Mr. Becerra recently won a House Democratic leadership post, and was apparently loath to give that up after concluding – as he told Los Angeles-based La Opinion – that trade "would not be priority No. 1, and perhaps, not even priority No. 2 or 3" for Mr. Obama.

Mr. Grassley finds that "extremely disappointing," aides said, given how critical exports will be to economic recovery.

Among others mentioned for the trade job recently: Dan Tarullo, a Georgetown University law professor who served in the Clinton administration, and former Rep. Harold Ford of Tennessee, head of the centrist Democratic Leadership Council.

Staff writer Gromer Jeffers Jr. in Dallas contributed to this report.