Watch President Trump hammer Senator McCain and the  weak  Senator Flake at an Arizona rally, where he also threw his support behind Dr. Kelli Ward:AP  Arizona Republican Sen. Jeff Flake s re-election race is becoming a case study in the GOP s convulsions among the establishment, a furious base, and angry donors.After bucking Donald Trump in a state the president won, Flake is bottoming out in polls. Yet Republicans look like they may be stuck with a hard-core conservative challenger who some fear could win the primary but lose in the general election.A White House search for a candidate to replace former state Sen. Kelli Ward in the primary appears to have hit a wall. And now conservatives want to turn Arizona into the latest example of a Trump Train outsider taking down a member of the GOP establishment. People are fooling themselves if they think Jeff Flake is anything but a walking dead member of the United State Senate,  said Andy Surabian, whose Great America Alliance is backing Ward. I don t see how he survives a primary. I don t see how he survives a general. The numbers just don t add up,  added Surabian, who worked at the White House as an adviser to Steve Bannon, then the president s top strategist.Despite discontent among some Republicans over Ward, Bannon met with her last week at a conservative conference in Colorado Springs to encourage her campaign, according to a Republican official who spoke on condition of anonymity to disclose the previously unreported private meeting.Ward unsuccessfully challenged Arizona s senior senator, John McCain, in last year s election, losing in the primary by a wide margin. But in Flake, she would face a more vulnerable candidate at a moment when the GOP establishment is on the defensive, facing a simmering anti-incumbent mood heightened by Republicans  failure to make good on seven years of promises to scrap Barack Obama s health care law.Flake is in danger of becoming the latest victim of this voter wrath. Yet rather than making an effort to soothe pro-Trump GOP voters, he s all but dared them to take him down by kicking off his campaign with an anti-Trump manifesto,  Conscience of a Conservative,  a book in which he bemoaned his party s failure to stand up to Trump in last year s presidential race. We pretended that the emperor wasn t naked,  Flake wrote.Trump, in turn, has lashed out at Flake on Twitter, calling him  toxic,  while praising Ward. White House officials say there s little chance Trump will have a change of heart over supporting Flake. One official, speaking on condition of anonymity to disclose private deliberations, said Trump is irritated not only by Flake s public criticism but by what Trump sees as the senator s attempts to use his critiques of the president to gain attention.Nevertheless, Flake, 54, insists he won t be getting out of the race. The primary is Aug. 29. 