From an interview with Fox News' Chris Wallace:

WALLACE: I know that three years is an eternity in politics. But how hard do you think President Obama will be to defeat in 2012?

PALIN: It depends on a few things. Say he played, and I got this from Buchanan, reading one of his columns the other day. Say he played the war card. Say he decided to declare war on Iran, or decided to really come out and do whatever he could to support Israel, which I would like him to do. But that changes the dynamics in what we can assume is going to happen between now and three years. Because I think if the election were today, I do not think Obama would be re-elected.

But three years from now things could change if on the national security threat —

WALLACE: You're not suggesting that he would cynically play the war card.

PALIN: I'm not suggesting that. I'm saying, if he did, things would dramatically change if he decided to toughen up and do all that he can to secure our nation and our allies. I think people would perhaps shift their thinking a little bit and decide, well, maybe he's tougher than we think he is today. And there wouldn't be as much passion to make sure that he doesn't serve another four years —

So there it is.  Palin read a Pat Buchanan article, and thinks that Obama would be well-advised to start a war with Iran.

The problem?  Well, here is the Pat Buchanan article, entitled "Will Obama Play The War Card?"

And guess what?  Buchanan argued against war with Iran.

Palin apparently didn't read beyond the headline.