"[The president] will go to that summit weakened," said Jeffrey J. Schott, a scholar at the Institute for International Economics in Washington.
More broadly, Clinton's uncertain status to negotiate trade deals may work against the United States in Santiago, Chile, next April, when nations throughout the Americas are scheduled to begin talks on a hemispheric free-trade zone to take effect by 2005.
"Latin American leaders will not seriously negotiate with the United States if we don't have fast-track authority," Schott said.
The lack of fast-track authority also poses potential problems for international talks scheduled over the next few years involving trade in agriculture, services, government procurement and other areas.
And it appears to wipe out possibilities for broad bilateral trade deals with Chile and other nations, possibly including New Zealand, Australia and Singapore.
"They [the Chileans] don't want to negotiate once with the administration and once with the Congress," said Jay Ziegler, spokesman for the U.S. trade representative's office.
Times staff writers Edwin Chen, Faye Fiore and Sam Fulwood III contributed to this story.