Mitt Romney just announced at CPAC that was suspending campaign operations, claiming that continuing to campaign would only increase the chances of a Democratic victory in the fall.
While we can't discount the reasoning entirely, politicians don't stop running for president unless they can't win. He almost certainly didn't like the polling data from the upcoming caucuses, which were widely seen as his chance to stabilize the ship. Implicit in his concession is a call for Republicans to suck it up and support McCain in the general election, although Huckabee and even Ron Paul will get some increased protest vote from here on in.
With McCain as the almost-certain nominee, we have the likelihood - for the second election in a row - of a sitting Democratic Senator, Zell Miller, now Joe Lieberman, addressing the Republican convention in support of its nominee.
(Colorado Media Matters notes whines that Lieberman is not, technically, a Democrat.)
CLARIFICATION: While Joe Lieberman is no longer technically registered with the Democratic Party, he is listed as an "Independent Democrat," and caucuses with the Democrats. If he chooses to run for re-election, it's a safe bet he'll do so as a Democrat.
Most people think of his as a Democrat, and most people will remember that he was the Democratic nominee for Vice President eight years ago. I'm sure the party, the networks, and the newspapers - properly mortified - will be at pains to point out he lost the primary, in advance of his speech.
FURTHER CLARIFICATION: Senator Lieberman was also permitted to retain his seniority by the Democratic caucus after his re-election, and serves as the Chairman of the Senate Homeland Security and Governmental Affairs Committee.
This is truly a distinction without a difference, but it's good to know that Mr. Soros's money is going to good use.