The Senate "Gang of Eight" immigration reform bill survived perhaps its toughest challenge late in the day, as the Senate Judiciary Committee refused to approve an amendment that would have allowed gays and lesbians to sponsor their partners for immigration in the same way married heterosexual couples would be able to do under the proposed legislation.

The amendment by Judiciary Chairman Patrick Leahy, D-Vt., was introduced and then withdrawn after he saw that his amendment could potentially kill the bill.

Republican members of the bipartisan "Gang of Eight" that co-wrote the immigration bill said they could not countenance the amendment and would walk away from the entire legislation if passed.

Democrats on the committee voiced support for what they saw as equal protection under the law, but said they would vote against the amendment to save the bipartisan compromise that held the immigration reform bill together.

"The result [if Leahy's amendment passes]: no equality [and] no immigration bill. Everyone loses," said Sen. Chuck Schumer, D-N.Y.

"The security and prosperity of our nation is too vital, too rare to let [the bill] fail now," Schumer said. "As much as it pains me, I cannot support this amendment if it will bring down the bill."

Sen. Al Franken, D-Minn., added, "It's wrong. Discrimination is wrong, but I can't kill this bill."