Last Thursday, Stephen Colbert had brilliant segment of Formidable Opponent, where he debated himself about Mitt Romney's positions. And in it, there was one key question he asked which lays to waste Romney's entire tax proposal.

BLUE-TIE STEPHEN: You are adorable! (in voice parents make to babies) Who got sucked in by Romney? You did!

RED-TIE STEPHEN: No I didn't.

BLUE-TIE STEPHEN: Yes you did!

RED-TIE STEPHEN: Knock it off.

BLUE-TIE STEPHEN: Who doesn't like when I talk like this? You don't!

RED-TIE STEPHEN: Hey, if anyone fell for it, it's you hardliners when you nominated Mitt. I mean, for Pete's sake, he gave us Romneycare, the inspiration for Obamacare!

BLUE-TIE STEPHEN: Which he will repeal and replace.

RED-TIE STEPHEN: With more Romneycare.

BLUE-TIE STEPHEN: Which he leaves up to the individual states. And I am sure Mississippi will step right up to the plate.

RED-TIE STEPHEN: Hey, he is looking out for the middle class.

BLUE-TIE STEPHEN: He's promising a 20% tax cut for the top 1%.

RED-TIE STEPHEN: Ah, but he's also promising to close their tax loopholes, so they'll still pay the same amount.

BLUE-TIE STEPHEN: Then... why cut their taxes?

RED-TIE STEPHEN: I... don't know. But I just don't see how a guy can change his beliefs overnight and still come off as credible in a debate!

BLUE-TIE STEPHEN: Oh, it's easy. Here, let's switch sides.

RED-TIE STEPHEN: Uh, OK.

(they switch sides)

BLUE-TIE STEPHEN: OK, so now you're me, and I'll pretend to be you. (in nerd voice) I have postulated the theory that Mitt Romney is actually a secret centrist pretending to be a conservative posing as a moderate. Ipso facto, I yield the remainder of my time. Now you do me.

RED-TIE STEPHEN: (in James Cagney voice) Meah, see, meah. I know Romney's embrace of moderation is merely a cover for actually being the ultraconservative he was in the primaries. Meah.

BLUE-TIE STEPHEN: Wow. I do a great DeNiro.

RED-TIE STEPHEN: Yes you do.

BLUE-TIE STEPHEN: Well Stephen, the point is, I agree with what you just said. Romney is a secret conservative. You win.

RED-TIE STEPHEN: Wait, no, wait. I was being you when I said that. So I actually lose.

BLUE-TIE STEPHEN: Does it really matter who won? As long as I did? OK, let's switch back.

(they switch sides again, with red-tie Stephen falling down)

RED-TIE STEPHEN: You tripped me!

BLUE-TIE STEPHEN: Sorry.

RED-TIE STEPHEN: Well, let's switch sides.

BLUE-TIE STEPHEN: No, we just did.

RED-TIE STEPHEN: I don't think so.

BLUE-TIE STEPHEN: No, we totally did. Anyway, thanks again for the book.

RED-TIE STEPHEN: Wait, no! You gave me the book! You even signed it for me.

BLUE-TIE STEPHEN: Nope. You signed it for me. "To Stephen: I complete you."

RED-TIE STEPHEN: Oh my God. I don't know who I am anymore.

BLUE-TIE STEPHEN: And we only switched positions once.

RED-TIE STEPHEN: Imagine how Mitt Romney must feel!

(wild audience laughter and applause)

BLUE-TIE STEPHEN: I bet he feels pretty good, cuz it's working.

RED-TIE STEPHEN: Well, you've got a point.

BLUE-TIE STEPHEN: And you sir...

BOTH STEPHENS: ... are a Formidable Opponent. We'll be right back.