The Senate voted today to kill an amendment to Sept. 11 legislation that would have stripped out a provision giving airport screeners collective bargaining rights, taking another step toward a confrontation with the president on the issue.

Senators voted 51-46 to table the amendment by Sen. Jim DeMint, R-S.C. The vote came as tensions between Democratic and Republican lawmakers over the issue reached new heights.

The legislation (S 4), intended to implement some remaining recommendations of the Sept. 11 Commission, would give collective bargaining rights and government whistleblower protections to screeners employed by the Transportation Security Administration. The White House has threatened to veto the legislation, contending that it would bar the Homeland Security Department from effectively assigning its screeners in the event of heightened threat.

In a letter to President Bush, 146 House Republicans pledged to sustain the veto, following the lead of 36 senators who pledged a week ago to do the same. Opponents of the provision now have sufficient support to block it from becoming law if Bush follows through on his veto threat.

House-passed Sept. 11 legislation (HR 1) also contains a provision to give collective bargaining rights to airport screeners.