Barack, Michelle Obama expected to refrain from endorsing in 2020 Dem primary: report
Flake: 'I hope' McSally wins bid to succeed me
"I think McSally will win. I hope she does. That's the only shot that obviously Republicans have to hold on to the seat, but it's even difficult then. This is going to be a hard-fought general election," Flake told reporters.
Flake, a vocal critic of President Trump who announced last fall that he would retire after this Congress, offered his support for McSally as she pushed to pull out a win in Tuesday's Senate GOP primary.
McSally is facing off against two conservative firebrands, former state Sen. Kelli Ward and former Maricopa County Sheriff Joe Arpaio, for a chance to compete in the November general election for the seat being vacated by Flake.
All three candidates competing in Tuesday's Republican primary have tried to tie themselves closely to Trump, who has relationships with each of the candidates.
Trump has declined to offer an endorsement in the race, though Sen. Cory Gardner (R-Colo.), the head of the National Republican Senatorial Committee, reportedly asked the president to back McSally in a recent phone call.
Ward has garnered negative headlines in recent days over her criticism of the late Sen. John McCain (R-Ariz.), while Arpaio was pardoned by Trump after being convicted of contempt of court for refusing to end racial profiling of Hispanics during immigration arrests.
The winner of Tuesday's GOP primary is likely to face Democratic Rep. Kyrsten Sinema (Ariz.) in the fall. The three-term congresswoman is well-funded and has avoided a grueling and bitter primary.
A compilation of polls by RealClearPolitics shows Sinema leading all three GOP candidates in hypothetical matchups, but defeating McSally by the smallest margin of the three.
The nonpartisan Cook Political Report lists the Senate race as a "toss up."