Vice President Cheney has been the most dangerous vice president we’ve had probably in American history. The idea he doesn’t realize that Article I of the Constitution defines the role of the vice president of the United States, that’s the Executive Branch. He works in the Executive Branch. He should understand that. Everyone should understand that. And the primary role of the vice president of the United States of America is to support the president of the United States of America, give that president his or her best judgment when sought, and as vice president, to preside over the Senate, only in a time when in fact there’s a tie vote. The Constitution is explicit. The only authority the vice president has from the legislative standpoint is the vote, only when there is a tie vote. He has no authority relative to the Congress.
Biden at the 2008 Vice Presidential debate