The 7 Senators to Watch on Brett Kavanaugh's Confirmation

Senate Republicans have a very narrow margin for error on the confirmation of Supreme Court nominee Brett Kavanaugh.

The GOP caucus has just 51 members, but it's unclear if Arizona Sen. John McCain, who is being treated for brain cancer, will be able to return to the chamber to vote. A 50-50 tie vote would be broken with a vote from Vice President Mike Pence.