I just heard a news rumor on the radio that Mitt Romney is about to announce that he's dropping out of the race.

Apparently there's an announcement now at CPAC.

Stay tuned.

12:50 -- He's just said McCain has more delegates and he's thanking everyone. No mention of any withdrawal yet.

12:52 -- ABC confirms the rumor.

12:54 -- More here.

But what's up at CPAC?

12:56 -- Breitbart quotes his speech:

WASHINGTON (AP) - John McCain effectively sealed the Republican presidential nomination on Thursday as chief rival Mitt Romney suspended his faltering presidential campaign.

"If I fight on in my campaign, all the way to the convention, I would forestall the launch of a national campaign and make it more likely that Senator Clinton or Obama would win. And in this time of war, I simply cannot let my campaign, be a part of aiding a surrender to terror," Romney will say at the Conservative Political Action Conference in Washington.

"This is not an easy decision for me. I hate to lose. My family, my friends and our supporters... many of you right here in this room... have given a great deal to get me where I have a shot at becoming President. If this were only about me, I would go on. But I entered this race because I love America, and because I love America, I feel I must now stand aside, for our party and for our country," Romney said.

McCain prevailed in most of the Super Tuesday states, moving closer to the numbers needed to officially win the nomination.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information.

12:58 -- Judging from what's here, I'd say it's a done deal.

12:59 -- Glenn Reynolds thinks so too, and links the Breitbart story.

01:03 -- I only heard a segment of the speech, but I think that's it. But now I'm listening to Romney POTUS on XM for more. I'm not sure whether it's the resignation speech, but he's talking about fighting the war on terror, and veterans issues, judicial appoinments, and the crowd is applauding. He's saying "you're with me all the way to the convention" and "fight on," so maybe he's changed his mind....

01:06 -- Uh oh. If I fight on, I'd be making it easier for Clinton and Obama to win.

Can't make my campaign aid a surrender to terror.

That's it. He's pulling out.

It's not all about me.

"I entered this race because I love America. Because I love America, I need to step aside."

We cannot allow the next president of the United States to retreat in the face of evil extremism.

A very decent man delivers a decent resignation speech.

He's out. It's final.

MORE: It looks like Bill Kristol got it right in the prediction he made late Tuesday night, when he said "I think Mitt Romney will pull out."

AND MORE: On POTUS I just heard G. Gordon Liddy say, "And now the general election can begin."

Strategically, this makes sense for the Republican Party as a whole, as they're now ahead of the game.

MORE: At Pajamas Media, Rick Moran has more on Romney's "Swift and Graceful Exit." (Via Glenn Reynolds.)