Despite a last minute push by administration officials and President Bush himself to bring wayward Republicans back into the immigration fold, GOP conservatives soundly defeated a massive immigration reform package Thursday morning, voting 46-53 against invoking cloture on the bill.

After the vote, Senate Majority Leader Harry Reid (D-Nev.) suggested the chamber might revisit the bill eventually. “It will come back, it’s just a question of when,” Reid said on the floor, later adding at a press conference that he was “very disappointed” in the vote but said, “We gave it the old college try.”

Reid tried to deflect attention away from the dozen Democrats who voted against cloture, saying, “The vast majority of Democrats support this. … Had this been a close vote, more Democrats would have voted for it.”

Reid said conversations already have begun about moving some parts of the immigration bill separately. For example, he said he may move both a bill to allow children of illegal immigrants get college financing and a measure to to allow more agricultural workers into the country.

Sen. Edward Kennedy (D-Mass.) vowed to return to the issue. “We will be back,” he said. “This issue is not going away.”

But conservative GOP opponents of the bill said the measure’s defeat was a victory for the grass-roots effort that rallied to oppose the bill.

“The only victor here is the American people,” said Sen. Jim DeMint (R-S.C.).

Added Sen. David Vitter (R-La.), “I don’t think the message could be any clearer than on this vote. … They didn’t even get a simple majority.”

The morning started off badly for a small group of bipartisan supporters of the bill as outside organizations from across the political spectrum protested outside the Capitol and flooded the Congressional phone system with angry calls to the point that it began suffering periodic shutdowns.

Even as bill supporters Kennedy, Reid and Sen. Arlen Specter (R-Pa.) pleaded with their colleagues to vote to end debate on the bill, Commerce Secretary Carlos Gutierrez and Homeland Security Secretary Michael Chertoff worked lawmakers as they made their way to the Senate floor for the vote.

With control of the floor firmly in his grip thanks to his use of the “clay pigeon” procedural tactic, Reid and supporters of the bill limited opponents to only 10 minutes of floor time just prior to the vote, while backers took nearly 50 minutes to extol the bill’s virtues.

Additionally, as Members began filing into the chamber, Reid even played on charges by bill supporters that opponents are little more than thinly veiled nativists and racists. While “My skin is very white,” Reid argued that color should not be the basis for immigration policies and that to not fix the system would jeopardize the nation’s identity as a melting pot.

Although Reid had predicted a close vote on the bill — and voting progressed at a slow pace as fence-sitting Republicans and Democrats were feeling out the political winds — once it became clear that the cloture motion would fail and thus kill the legislation, it quickly became an all-out jail break.

Scores of lawmakers dropped their support for a bill they had voted to take up earlier this week, including Sens. Ben Nelson (D-Neb.), Jim Webb (D-Va.), Ted Stevens (R-Alaska), Lisa Murkowski (R-Alaska), Mark Pryor (D-Ark.), Richard Burr (R-N.C.) and Tom Harkin (D-Iowa). Even Minority Leader Mitch McConnell (R-Ky.) — who had not only backed the bill previously but had engineered this week’s tightly controlled debate with Reid over the objections of conservatives — joined those who flocked to the opposition.

In fact, conservative opponents of the bill said the heavy-handed tactics used by McConnell and Reid to move the bill ultimately played a part in its defeat. “I do feel this vote was a rejection of the clay pigeon procedure. … I think that was a factor in many people’s votes,” said Sen. Jeff Sessions (R-Ala.), one of the leaders of the conservative opposition.

Sessions and other conservatives also said that the manner in which the bill was brought back to life had caused significant damage to the Republican Conference, both within the Senate and the party more broadly. “We need to be careful we don’t walk into such adverse circumstances” in the future, Sessions said.

Vitter agreed, saying that while the debate “created real divisions within our party,” McConnell’s switch to the opposition at the end of today’s vote was a step in the right direction. “Sen. McConnell started that healing process today when he voted no,” Vitter said.

On the House side, Democratic leaders didn’t sound keen on moving an immigration bill on their own after the Senate’s failure.

“We’ve said of course that if the Senate can’t act, then us spending a lot of effort and time to pass a bill may not be productive,” said House Majority Leader Steny Hoyer (D-Md.), although Hoyer cautioned that he hadn’t had a chance to talk to Senate leaders. Hoyer also noted that House leaders do consider the issue to be important.

House Majority Whip James Clyburn (D-S.C.) blamed Bush for the measure’s failure, asserting he had broken a vow to deliver at least half of the Senate’s Republicans.

“It looks like the president has failed to keep his end of the bargain,” Clyburn said.

The South Carolina lawmaker declined to specify whether the legislation will reach the House floor in the 110th Congress, shifting responsibility to the White House.

“This is the president’s initiative and it’s up to him where we go from here,” he said.

Congressional Hispanic Caucus Chairman Joe Baca (D-Calif.) similarly criticized Bush, who had met with Hispanic lawmakers earlier this year at the White House to discuss the legislation.

“Mr. President, this is an embarrassment to you, that you didn’t deliver,” Baca said at an afternoon press conference. He continued, shouting: “Mr. President you should have been there. You should have been leading the fight.”

The Hispanic Caucus, which currently is made up of only of Democratic lawmakers although it is technically nonpartisan, also used the Senate vote to encourage increased registration of Latino voters and voter turnout.

Rep. Luis Gutierrez (D-Ill.) said the CHC will use the July Fourth recess to determine how it will pursue the legislation in the 110th Congress.

“We need to carefully consider that question and reflect upon that question,” he said. “We should prepare ourselves for the 10th of July so that we have a plan.”

Baca later added: “There is a possibility we could bring it back.”

Gutierrez noted, however, that the CHC would continue to oppose efforts to move the legislation in smaller pieces, rather than a single package.

Emily Pierce, Jennifer Yachnin and Steven T. Dennis contributed to this report.