A day after 70 senators dealt a blow to the Bush administration’s plans to give Mexican trucks access to U.S. highways, several Republicans kept the lawmaking body bottled up with procedural issues.

The Senate is debating an amendment to the bill that will fund the Department of Transportation; the amendment could slow or block plans to open the U.S. border to Mexican trucks on Jan. 1. It toughens standards on drivers’ records, vehicle inspections and insurance for Mexican carriers. The Bush administration says the plan is unfair to Mexicans and could result in sanctions. The president says he will veto the funding bill if it contains the amendment.

On July 26, key Republicans staged a filibuster hoping to alter or strip the amendment from the bill. But all 50 Democrats joined by 19 Republicans and one independent, shut down the filibuster.

Earlier in the same day, the Senate dealt defeat to an amendment sponsored by Sen. Phil Gramm (R-Texas) that would have prevented the government from imposing special safety sanctions on Mexican trucks. Gramm and Sen. John McCain (R-Ariz.) then began to filibuster the issue trying to force senators into a compromise plan.

Those tactics continued July 27 and threatened to keep the Senate in session late into the night.

Under the North American Free Trade Agreement Mexican trucks are supposed to have access to U.S. highways, but for the last eight years the U.S. has kept the trucks limited to within 20 miles of the border. The Bush administration wants to open the border by Jan. 1, concerned that Mexico will be able to impose trade sanctions under NAFTA. The Department of Transportation has already proposed regulations dealing with Mexican carriers, and its funding bill seeks new monies for additional facilities and inspectors along the border.

Congress, however, is skeptical. The House of Representatives passed a similar bill to the Senate’s amendment a few weeks ago. When the Senate took up transportation funding Sen. Richard Shelby (R-Ala.) and Sen. Patty Murray (D-Wash.) sponsored the amendment toughening the standards Mexican carriers must meet.

Labor organizations, chief among the opposition, praised Bush’s defeats this week. “I congratulate the Senate on today’s vote and urge adoption of a transportation spending bill which includes the Murray-Shelby truck and bus safety provisions,” said Sonny Hall, president of the AFL-CIO Transportation Trades Department. “Nothing less is acceptable to the nation’s several million transportation workers. The American people, including the hundreds of thousands of commercial drivers we represent, reject the idea that our country should ignore the well-documented safety threats posed by allowing trucks and buses from Mexico unencumbered access to our highways.”

“Today the U.S. Senate took a strong stand for highway safety,” said James P. Hoffa, president of the International Brotherhood of Teamsters. “We cannot close our eyes, let unsafe Mexican trucks across our border and hope everything turns out alright. Mexico must meet its end of the NAFTA bargain and establish a real safety regime.”

Trucking groups are split on the issue. The American Trucking Associations favors allowing Mexican trucks into the United States, while the Owner Operator Independent Drivers Association has sided with labor on the issue.