This is a devastating blow to John McCain’s candidacy. Watch Colin Powell explain his reasoning at length here:

He is impressed by Obama’s style and substance, by Obama’s choice of running mate, and by the way Obama has handled himself during the economic crisis. He admires McCain but is disturbed by the choice of Sarah Palin (whom Powell does not consider ready to be president) and the way McCain and senior Republicans have tried to attack Obama this fall.

Powell is not my favorite person, but the media love him, and millions of Americans admire him. I’d been hearing rumors for months that Powell might endorse Obama, but I was skeptical.

Also in the news this weekend, Obama’s campaign announced that they raised $150 million in September, and Obama drew crowds of 100,000 in St. Louis and 75,000 in Kansas City yesterday.

Time is running out for McCain. I don’t see how he changes the dynamic.

UPDATE: So I took the kids to “sample Sunday” at Picket Fence Creamery in Woodward today, and there was a car parked in the lot with a bumper sticker I’d never seen. It asked, “Who will be your commander in chief?” On the left side, there was a head shot of McCain with an American flag backdrop, and on the right was that photo of Obama in Muslim garb when he visited Africa. A woman was sitting in the car talking to some people standing next to it. As I walked by, I said, “Colin Powell doesn’t agree with your bumper sticker.”

They looked confused, so I said, “Colin Powell said this morning that he’s voting for Obama. I guess he knows what it takes to be commander in chief.”

That felt good.