The Senate Finance Committee voted Tuesday to give President Bush broad latitude to negotiate a free trade agreement between the United States and Mexico.

By a 15-3 vote, the panel agreed to extend by two years the so-called fast-track authority by which the president can negotiate a treaty without fear of it being altered by Congress.If such fast-track authority is enacted by both the House and Senate, Congress would then be left only with the option of voting up or down any trade treaty that Bush negotiated with another nation or group of nations.

The Senate Finance Committee vote came as the House Ways and Means Committee was considering an identical measure. The Congress is facing a June 1 deadline for abrogating the president's fast-track trade negotiating authority - after which this authority will be automatically extended.

Tuesday's vote was the second victory in as many weeks for Bush, who has been aggressively promoting a new treaty creating a free trade zone between the United States and Mexico.

Last week, House Majority Leader Richard Gephardt, D-Mo., said he would support continued fast-track negotiating authority, as requested by the administration. But Gephardt also said he would insist that the House be allowed to amend such a treaty through implementing legislation if it did not meet his standards.

Fast-track authority gives U.S. trade representatives - and the president, for that matter - the power to negotiate treaties that cannot be changed by Congress. The House and Senate can merely accept or reject such a pact within 60 days of the time it is negotiated. Bush has said that without renewal of the legislation giving the executive branch of government such trade negotiation flexibility, the United States could not attempt to work with Mexico to end the two countries' trade tariffs.

The vote Tuesday affects not only the U.S.-Mexico free trade deal but also a free trade pact with Canada and general agreements on trade that the United States has with more than a hundred other nations.