Rep. Robert J. Portman was nominated to be the nation’s top trade negotiator, as President Bush seeks support in Congress for his agenda of using international trade to spur economic growth at home.

Mr. Portman, a 49-year-old Republican from Ohio, would replace former American Trade Representative Robert Zoellick, who left to take the no. 2 post in the State Department in February. At a press conference from Washington yesterday, Mr. Bush urged the Senate to quickly approve the nomination, saying Mr. Portman “has shown he can bring together people of differing views.”

That ability will be critical as Mr. Bush tries to spur along global trade talks, which have hit roadblocks over agriculture subsidies, and convince lawmakers that new trade accords still make sense against the backdrop of a record trade deficit and declining manufacturing employment. Mr. Bush really sees Mr. Portman as a “good liaison with Capitol Hill,” said Frank Vargo, vice president of the National Association of Manufacturers.

Mr. Bush will face at least three tests of his trade agenda this year: winning passage for a Central American trade accord; keeping his fast-track trade authority, and halting congressional efforts to withdraw America from the World Trade Organization.

“This appointment means there is White House support for these heavy battles on trade that are coming up,” said a fellow at the Institute for International Economics in Washington, Gary Hufbauer.

Rep. Benjamin Cardin of Maryland, the ranking Democrat on the trade subcommittee of the House Ways and Means Committee, and Rep. Charles Rangel, a New York Democrat, praised the selection of Mr. Portman.

Mr. Bush said that Mr. Portman will be a member of his Cabinet. Democratic lawmakers criticized the administration in recent weeks for threatening to downgrade the position of trade representative.

Mr. Portman represents Ohio’s second district, which includes Cincinnati. While in Congress, he helped prepare Vice President Cheney for last year’s electoral debate and campaigned for Mr. Bush in Ohio. Business groups say Mr. Portman’s experience representing Ohio is illustrative of both the failures and successes of the Bush administration’s trade policy.

Ohio shed 198,000 jobs since Mr. Bush took office, including 17% of its total factory employment. Those losses helped spur criticisms of what some factory owners say is Bush’s weak effort in confronting unfair imports from China and that country’s undervalued currency.

“For manufacturers that want to make their products in the United States, this is a real slap in the face,” said Alan Tonelson, a research fellow at the U.S. Business and Industry Council, which represents closely held and family owned manufacturers.

America has shed 2.8 million factory jobs since Mr. Bush took office in 2001, while the American trade deficit grew to $56 billion a month, a 60% increase.

The pro-trade National Association of Manufacturers and the National Foreign Trade Council both ranked Mr. Portman among their top supporters because of his votes in favor of free-trade agreements with Morocco, Australia, Chile, and Singapore.

He now must convince lawmakers to support a stalled trade agreement between America, five Central American nations and the Dominican Republic.