Democrats began congressional scrutiny of the North American Free Trade Agreement by lashing out at what they said was election-year manipulation of an accord that won't be put to a vote before next spring at the earliest.

A Senate Finance Committee hearing Tuesday, with U.S. Trade Representative Carla Hills the sole witness, kicked off consideration of a pact that would link the United States, Mexico and Canada in the world's richest trade zone by eliminating tariffs.The committee's chairman, Sen. Lloyd Bentsen, and other Democrats signaled to Hills their anger over the Bush administration's use of the proposed treaty to score points with voters.

"What I've seen over the last two weeks isn't responsible - it's pure politics and the administration knows it," said Bentsen, D-Texas. "Politicizing this agreement will not help its prospects in Congress."

Bentsen, who pointed to his involvement last year in lining up Democratic support for the trade talks, warned the administration not to use the treaty for partisan gain.

"The plain fact is, Ambassador Hills, you would not be here today if it were not for Democratic support for that negotiating authority," he said.

Congressional Democrats have been irked by President Bush's repeated free trade-related attacks on Democratic rival Bill Clinton. In recent campaign appearances across the nation, Bush has claimed that the Arkansas governor is waffling over endorsing the trade agreement.

Clinton has said he favors the idea of free trade with Mexico but wants to make sure environmental and labor standards are addressed before endorsing a treaty.

"For President Bush to suggest that Gov. Clinton or any of us in this Congress should endorse a treaty which we have not had the opportunity to review would be the height of irresponsibility," said Sen. Max Baucus, D-Mont., who chairs an international trade subcommittee.