Graham, who also served two terms as Florida's governor, chaired the Senate Intelligence Committee after the 9/11 attacks. He also made an unsuccessful bid for the 2004 Democratic presidential nomination.
The House narrowly voted in February to impeach Mayorkas for his handling of the border, arguing in the two articles that he "willfully and systematically" refused to enforce immigration laws.
Oklahoma is the two-time defending champion and has won five of the past seven national titles, but Cal and Stanford enter the championships posting some of their best scores of the season.