Following up on Ace’s post here is Biden telling Chris Matthews back in 2007 that he is deadly serious about attempting to impeach Bush if he goes to war in Iran without congressional authorization:

Matthews: You said that if the President of the United States had launched an attack on Iran without congressional approval that would have been an impeachable offense. Do you want to review that comment you made? Well how do you stand on that now?

Biden:Yes I do. I want to stand by the comment I made. The reason I made the comment was as a warning. I don’t say those things lightly, Chris, you’ve known me for a long time. I was chairman of the judiciary committee for 17 years or its ranking member. I teach separation of powers and constitutional law. This is something I know. So I got together and brought a group of constitutional scholars together to write a piece that I’m going to deliver to the whole United State Senate pointing out the President has no constitutional authority…to take this nation to war against a county of 70 million people unless we’re attacked or unless there is proof we are about to be attacked. And if he does, if he does, I would move to impeach him. The House obviously has to do that but I would lead an effort to impeach him. The reason for my doing that, I don’t say it lightly, I don’t say it lightly. I say it because they should understand that what they were threatening, what they were saying, what it was adding up to be, what it looked like to the rest of the world we were about to do would be the most disastrous thing that could be done in this moment in our history that I could think of.