Here's how John McCain's death will shift the political landscape

As the tributes roll in honoring John McCain, his home state Arizona and the U.S. Senate face some serious decisions on how to fill the seats left vacant by his death from brain cancer on Saturday.

The two-time presidential hopeful and Vietnam war hero spent his decades in the Senate fighting for lower taxes, enacting campaign finance reform, tightening abortion laws, and expanding the Second Amendment, and he’s served as head of the Senate Armed Services Committee for the past three years. He famously stopped the repeal of the Affordable Care Act with his dramatic vote in 2017, and he's been one of the most outspoken Republicans against President Trump.

Here’s a run-down of the likely political consequences of his passing.

Under Arizona state law, the governor (now Doug Ducey) can pick McCain’s replacement as soon as he wants as long as his replacement is a member of McCain’s party. His pick will fill McCain’s seat for the next two years, until a 2020 special election that will fill McCain’s seat for the final two years of his term. Then, in 2022, there will be an election for a full six-year term in his seat.

Ducey announced he plans to wait until after McCain’s funeral to appoint someone, but the seat is unlikely to stay vacant for long — some journalists believe his replacement will be announced within the next month. Ducey’s pick will no doubt gather increased scrutiny this year since the governor is up for re-election. But Arizona leans red, and Ducey is the favorite for re-election, so there isn’t too much pressure on the governor.

Ducey hasn’t explicitly said anything about his choices yet, but some journalists and pundits have pointed to McCain’s widow, Cindy McCain, to take over her late husband's seat. Cindy, 64, doesn’t have a background in politics, but wives taking over for their husband’s seats isn’t that uncommon: It’s happened almost 50 times, according to the Washington Post.

However, Ducey might want to put a more reliable Republican in the seat. In 2017, McCain voted in line with Trump 80 percent of the time, at the fifth-lowest rate of any Republican senator, according to FiveThirtyEight’s Trump score.

According to the Arizona Republic, Ducey’s short list also includes Kirk Adams, a former state lawmaker and Ducey’s chief of staff who ran an unsuccessful bid for Congress in 2012; Barbara Barrett, Arizona’s first female gubernatorial candidate; former Sen. Jon Kyl; former Reps. Matt Salmon and John Shadegg; Karrin Taylor Robson, a member of the Arizona Board of Regents; and Eileen Klein, Arizona’s State Treasurer.

The Senate might be getting even more Republican without McCain. He was outspoken in his opposition to the president and his administration, and Trump’s administration needs all the support it can get in the Senate. While McCain was out for most Senate votes while he was receiving treatment during the past year, the Senate was split just 50-49 in favor of the GOP. With a more reliable Republican in his place, that could give a stronger majority to Republicans.

It also hurts Republicans who've been critical of Trump and his administration, now an even smaller cohort. Without many allies in the GOP, these critics will have a more difficult time bucking party leadership and stalling Senate GOP initiatives. Critical Republicans Sen. Bob Corker of Tennessee and Sen. Jeff Flake of Arizona are both retiring from the Senate after the completion of their terms.

McCain, a decorated combat pilot and prisoner of war for over five years in the Vietnam War, has been chairman of the Senate Armed Services Committee since 2015 and was the ranking Republican for several years before then. He used his perch on the committee to steer issues like supplying lethal arms to Ukraine and the ban on transgender troops from the military.

In his absence, if Republicans hold the Senate in November elections, Oklahoma Republican Sen. James M. Inhofe will become chairman of the Senate Armed Services Committee. Inhofe is a devout Trump supporter, so it will be much less likely that he would push back against the White House with the same fervor as McCain.

Without McCain, and with a reliable Republican in his seat, Republicans would be able to relax a bit more about the upcoming confirmation of Brett Kavanaugh, Trump’s appointee to replace retiring Supreme Court Justice Anthony Kennedy. McCain’s replacement might not make a huge difference since there aren’t signs that any Republican, including McCain, would vote against Kavanaugh’s confirmation. Even if McCain’s replacement votes against Kavanaugh along with every single Democrat, the Republicans would have 50 votes, and Pence could cast the 51st deciding vote.

McCain’s body will lie in state at the Arizona Capitol on Wednesday, on what would have been his 82nd birthday, according to Ducey. After that, he’ll lie in state at the Capitol Rotunda in Washington, D.C. He’s only the 32nd person ever in U.S. history to get that honor.

Cover: Sen. John McCain speaks on a variety of topics with employees at Robertson Fuel Systems Tuesday, June 30, 2015, in Tempe, Ariz. The defense contractor designs and builds equipment to protect ground vehicles and combat aircraft. (AP Photo/Ross D. Franklin)