Voters go to the polls Tuesday in Florida and Arizona, and two powerful incumbents โ Sen. John McCain (R-Ariz.) and Rep. Debbie Wasserman Schultz (D-Fla.) โ face unusually strong primary challenges. McCain is expected to survive a long-shot bid to unseat him by State Sen. Kelli Ward (R), but is hoping for a big enough win to assuage doubts about his general election fight against Rep. Ann Kirkpatrick (D). Wasserman Schultz, who stepped down as Democratic National Committee chairwoman in July amid leaked emails showing DNC skepticism over Sen. Bernie Sanders, faces well-funded challenger Tim Canova, a law professor endorsed by Sanders. Florida Democrats will also choose between Rep. Patrick Murphy and Rep. Alan Grayson to determine which one faces Sen. Marco Rubio (R), expected to easily win his GOP primary on Tuesday.