Washington, D.C. ? Proponents of a broad immigration measure beat back challenges Thursday that could have scuttled the bill, including efforts to phase out a temporary worker program and bar millions of unlawful immigrants from gaining legal status.

The Senate overwhelmingly endorsed the legalization program, a cornerstone of the bipartisan plan. It also would tighten border security and create a strict verification program to deny jobs to illegal immigrants.

By a 66-29 vote, senators rejected an amendment by conservative Sen. David Vitter, R-La., that would have removed the chance for the nation’s estimated 12 million unlawful immigrants to live and work legally in the U.S. and eventually become citizens.

Sen. Pat Roberts, R-Kan., voted yet to reject the amendment. Sen. Sam Brownback, also a Republican, did not vote.

Earlier, in a 49-48 vote, the Senate rejected a proposal by Sen. Byron Dorgan, D-N.D., to end the temporary worker program after five years.