Appearing Monday on the Fox News Channel, Sen. Tim Kaine (D-VA) argued that former Vice President Joe Biden shouldn’t answer mounting questions from the media whether or not he supports packing the U.S Supreme Court because it’s “not his business.”

A partial transcript is as follows:

BILL HEMMER: Why won’t he answer that question?

SEN. TIM KAINE: I haven’t asked him, but I have a pretty good idea: Because it’s not his business. The Constitution gives no power to the president or vice president to pack the court. I heard the Senator Ernst say he won’t pack the court. It’s not a presidential responsibility. Congress, according to Article I of the Constitution, sets the composition. So that’s why it’s not even a part of the campaign plan.