Rahm Emanuel will "go through walls" to advance the president's agenda, the White House Chief of Staff said last night.

Here's how Emanuel described his role in the White House while speaking to PBS's Charlie Rose last night:

ROSE: Why did Barack Obama want you?

EMANUEL: I think I'm the fundamental core. He had a robust legislative agenda and knew I had been on both sides of Pennsylvania Avenue.

Second, he knew I was going to always have his back as his chief of staff, and that I will go through walls to help get what the president wants done. And somebody that had been in politics as both a member of Congress but also been in the White House and knows the kind of rhythm of the White House.

And fundamentally that I was going to be loyal to him and give him unvarnished assessment of what I think the tradeoffs and the equities that you're constantly weighing.

Remember, in the White House, Charlie, as I always describe it, there are only two types of decisions -- bad and worse, and immediate and emergency. And that's the grid they're on.