In Arizona’s Senate race, a long-term incumbent faces a rising national tide.

John McCain has been one of the Grand Canyon state’s US Senators for nearly three decades. But will he be dragged out of office by Donald Trump’s falling national popularity? As part of our series covering key Senate races in the 2016 election Barbara Norrander writes that in the Arizona race, McCain’s challenger, Ann Kirkpatrick – though behind in the polls – could benefit if Republicans are unwilling to vote for Donald Trump stay at home in November or if there is a surge in Latino voters.