Bush and Cheney work as a team. I admit it's kinda nice that the Veep isn't just somebody who sits around waiting for the Pres. to die anymore, which was formerly the case.
Anywho, the real answer, while politically incorrect to say, is, "We're appearing so we can help you out. The team is the team, and the team can answer your questions. We're not going to put up with you trying to separate us and pit us against each other. We're the leaders of the country, not 2 kids you pulled over for smoking dope -- you aren't going to separate us just to try to find discrepancies in our stories to knit-pick."
But, then again, these quips are why I'll never be in that position.
And Bush did fine answering last night on his own. If you aren't keen and alert when you step into the presidency, you become keen and alert soon thereafter. It's a job that demands one rise to the occassion. 15-18 hour days, ost every day -- it ain't an easy job.