Meeting with reporters over breakfast, the quartet promised to scuttle future accords that fail to crack down on trading partners that seek commercial advantage by underpaying workers and despoiling natural resources.

Most free traders, including many Republicans, say using trade deals to police such practices actually ends up harming the U.S. economy.

Trade experts said the tough line laid down by the four could doom pending bilateral free-trade agreements with Peru and Colombia; the 15-year-old Andean Trade Preference Act designed to combat drug trafficking; a decades-old program intended to promote economic growth in poor countries by leveling U.S. duties on more than 4,600 products; and the already beleaguered negotiations on a new global free-trade agreement.

Recalling his support 13 years ago for the North American Free Trade Agreement, Sen. Dick Durbin of Illinois echoed the widely held view among politicians and trade analysts that NAFTA's side agreements on protecting labor rights and the environment have been ineffectual.

“I feel betrayed,” said Durbin, who will hold the second-highest rung in the Senate leadership ladder as majority whip.

“Many of us believe globalization is as inevitable as gravity. But we have to move forward if we are going to have trade agreements with something that is sensible for American workers and businesses and for the future of our planet,” Durbin said.

Reid and Durbin were joined by Sens. Charles Schumer of New York, the newly named vice chairman of the Democratic caucus, and Patty Murray of Washington, caucus secretary. Those are the third-and fourth-ranking positions in theDemocratic leadership lineup.

Reid has been a consistent opponent of most free-trade deals and, along with Schumer, voted against NAFTA in the fall of 1993.

Murray, asserting that a third of all jobs in her state depend on trade, voted for the pact that linked the United States, Canada and Mexico in NAFTA, as well as other similar deals.

But, she added, “Where we have failed in this country is to enforce those trade agreements.”

Alan Tonelson, a research fellow at theU.S. Business and Industrial Council Educational Foundation and a prominent free-trade skeptic, contendedthat past agreements have in fact amounted to little more than “outsourcing deals.”

“It is great to see that more and more mainstream Democrats . . . might be waking up to this, finally,” he said.

Bill Frenzel, who championed free-trade deals as a Republican during a 20-year career in the House that ended in 1991, noted the Senate's traditional embrace of agreements such as NAFTA and said the emerging hard-line stance by Reid and his team “is very frightening.”

Frenzel, now a trade expert at the Brookings Institution, suggested thatit was a payback for organized labor's efforts to help Democrats gain majorities in the House and Senate in the midterm elections.

“Labor did its thing for Democrats in this election, and there is a quid pro quo  that is about to be delivered,” Frenzel said.

In addition to considering a variety of pending agreements with other countries, Congress will face a decision next summer on whether to renew the fast-track law, which restricts Congress to only accepting or rejecting trade agreements in their entirety.

Durbin said in a brief interview that fast-track's fate may well be linked to working out an understanding with the administration that future trade deals should contain enforceable provisions on labor rights and environmental protections.

Many former trade negotiators and other experts say that foreign governments are generally reluctant to accept such requirements.

However, a bilateral trade agreement with Jordan six years ago requires the two countries to enforce the labor and environmental laws already on their books.

Gary Hufbauer, a trade expert with the Peterson Institute of International Economics, said the view of the new Senate leadership could complicate things as trade deals with Peru and Colombia await congressional action.

“To get them through is going to require a real conversion on the road . . . to Lima,” Hufbauer said. “That is going to be real heavy lifting by the moderates.”