GOP lawmakers told the Washington Times they did not think the so-called Merida Initiative, named after the historic Mexican city in the Yucatan, would pass because it had been glommed on to a supplemental funding bill for the war in Iraq and Afghanistan.

"The supplemental spending bill is the not the appropriate vehicle for this particular funding initiative," said Rep. Duncan Hunter, R-Calif.

Some Republicans added that they had doubts about the effectiveness of the plan on the assumption that Mexican law-enforcement agencies were riddled with corruption and would undermine the Merida program.

The Times said Mexico has been urging passage of the plan, which would improve coordination of anti-drug efforts among the United States, Mexico and nations in Central America.