Biden said the vice president's only role is to support the president and to preside over the Senate "only in a time when in fact there's a tie vote. The Constitution is explicit."

Early vice presidents, such as Thomas Jefferson, actively exercised that role, the vice president still keeps offices at the Capitol, and scholars say it wasn't until the middle of the 20th century that the vice president had an office at the executive office building.

The president pro tempore, usually the senior senator from the majority party, takes over only when the vice president is absent. In recent practice, as the vice president has taken a bigger role in the executive, that's meant the Senate operates almost all of the time without the vice president in the chair.

"I'm thankful the Constitution would allow a bit more authority given to the vice president if that vice president so chose to exert it in working with the Senate and making sure that we are supportive of the president's policies and making sure too that our president understands what our strengths are," she said.