What happens if brain cancer forces John McCain to leave Senate?

PHOENIX — Should U.S. Sen. John McCain (R-Ariz.) be forced to leave the Senate following his brain cancer diagnosis, what happens to his seat?

“If he makes a decision that it is better to take care of himself or he can’t continue, there is a process in place,” Valley political expert Stan Barnes said Thursday.

That process begins with Gov. Doug Ducey, who would be required to appoint a replacement from McCain’s party.

“A Republican — because John McCain is a Republican — and that person would serve until the very next election,” Barnes said.

Should McCain opt to retire sooner rather than later, the “next election” would be the 2018 race. The winner of the election would then serve out the remainder of McCain’s term.

Senate rules were not overly specific on who would take over as chairman of the Senate Armed Services Committee, though that role is typically offered to the senator with the most experience on the committee.

The issue was further obfuscated because of a 1995 Republican Party rule changed that allowed individual senators serving on the same committee to vote for the party’s ranking member, regardless of seniority.

The process of possibly filling McCain’s seat differed from the one used to replace former U.S. Rep. Gabrielle Giffords (D-Ariz.), who resigned from the House after she was shot in the head at an event in 2011.

Because she left her seat during the first session of Congress, House rules required her spot to be filled by a special election. Had she left during the second session, her seat may have been filled or left vacant until the next election, depending on the timing.

However, it did not appear as if Arizona’s senior senator was prepared to step down anytime soon. Just one day after making his diagnosis public, he said in a tweet that he planned to return to work.

I greatly appreciate the outpouring of support – unfortunately for my sparring partners in Congress, I'll be back soon, so stand-by!

— John McCain (@SenJohnMcCain) July 20, 2017

U.S. Sen. Jeff Flake (R-Ariz.) said his colleague would likely be unhappy doing anything but returning to the world of politics.

“I don’t think he’ll be happy unless he’s in the thick of things,” Flake told KTAR News 92.3 FM’s Arizona’s Morning News on Thursday. “That’s who he is.”

McCain, 80, was diagnosed with glioblastoma, the most aggressive form of cancer that begins in the brain.

South Carolina Sen. Lindsey Graham said his closest ally in the Senate sounded strong when the pair spoke on the phone after the surgery.

“He wants to come back so bad he can’t stand it,” Graham said. “I think they won’t let him fly for a week. But I think he would walk back if they would let him.”

KTAR News’ Jim Cross and the Associated Press contributed to this report.

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