WASHINGTON -- I asked one of the few conservative Republican senators who stuck with President Bush on immigration to assess how Senate Republican Leader Mitch McConnell handled the issue. Asking not to be quoted by name, he replied: "If this were a war, Sen. McConnell should be relieved of command for dereliction of duty." Not only did the minority leader end up voting against an immigration bill that he said was better than the 2006 version that he supported, but he also abandoned his post, keeping off the floor during final stages of Senate debate.

Although I never before had seen a Senate party leader completely bail out of a major legislative fight, relieving McConnell of command seems too drastic. He until now had high marks from colleagues during his six-month leadership following four dreary years under Bill Frist. McConnell's non-performance on immigration derived from general Republican malaise going well beyond a single issue.

It is difficult to exaggerate the pessimism about the immediate political future voiced by Republicans in Congress when not on the record. With an unpopular president waging an unpopular war, they see electoral catastrophe in 2008 with Democratic gains in both House and Senate and Hillary Clinton in the White House. In such an atmosphere, these lachrymose lawmakers for several months have faced an increasingly hysterical onslaught from constituents demanding the death of the "amnesty" for immigrants that they hear vilified daily on talk radio.

These callers recently swamped phone lines to Republican Congressional offices (as well as the White House) with threats that they never would vote again for anybody supporting "amnesty." While that intimidated previous supporters of the immigration bill, its opponents reacted to the xenophobia of their backers as a ray of light in the bleak political landscape.

"We did it!" exulted freshman Sen. Jim DeMint of South Carolina, one of the bill's leading Republican opponents, e-mailing financial contributors (including some who never had given DeMint any money). "When the U.S. Senate brought the Amnesty bill back up this week, they declared war on the American people." The message concluded with a request for a donation to DeMint's 2010 re-election fund. DeMint was not the only triumphant e-mailer. Newt Gingrich, eyeing a presidential run, declared to contributors "a soaring victory for the American people" by defeating the "Bush-Kennedy-McCain bill."

DeMint and Gingrich gloated because 12 Republican senators who had supported the bill succumbed to pressure and voted against it Thursday -- most without prior explanation, as did McConnell. He is up for re-election in Kentucky in a difficult 2008 for Republicans, with the state's other GOP senator, Jim Bunning, beating a tattoo on immigration. Among the switchers were Sen. Saxby Chambliss, who was booed last month at the Georgia Republican convention for supporting the bill and faces a re-election fight next year, and Sen. Richard Burr, under attack in his state of North Carolina.

McConnell was among six switchers who voted no after the 40 senators needed to kill the bill were recorded. Another late switcher was Sen. Sam Brownback, seeking the Republican presidential nomination as the candidate of the Right. He voted for the first cloture motion on Tuesday to keep the immigration bill alive, and put out a press release on his presidential website explaining his vote. On Thursday, he voted again for the bill. But when it became clear the measure had failed, he changed his vote from aye to nay and scrubbed his earlier statement from the Internet.

Unlike McConnell, the second and third ranking Senate GOP leaders -- Trent Lott and Jon Kyl -- stuck with the bill despite intense pressure in their respective home states of Mississippi and Arizona. So did Sen. Lindsey Graham, facing threats of Republican primary opposition in South Carolina next year. So did Sen. John McCain, despite damage to his crumbling presidential campaign.

"This isn't a day to celebrate," McConnell said in his post-mortem, contradicting victory cheers by DeMint and Gingrich. Indeed, Republicans drove another nail in George W. Bush's political coffin and undermined hopes for the growing, winnable Hispanic vote. Contending the time "wasn't now" for immigration, McConnell added: "It wasn't the people's will. And they were heard." He was blaming Republican failure on his fellow citizens, which seldom works in politics.