Arizona Sen. Jeff Flake is a vocal critic of President Donald Trump and recently published an anti-Trump manifesto in which he accuses his party of enabling the Trump presidency. | Bob Christie/AP Photo White House Trump aides worry he hurt hopes of defeating Flake The president gave a shout-out to Kelli Ward, who even some White House aides believe would be a weak challenger.

President Donald Trump upended the Arizona Senate race on Thursday by signaling support for an underdog primary challenger — a move that went against the wishes of his advisers and potentially undercut their efforts to unseat GOP Sen. Jeff Flake.

The president gave a shout-out on Twitter to Kelli Ward, a conservative former state senator running to take out Flake in a primary next year. Flake, of course, is a vocal Trump critic who refused to endorse the real estate mogul during the 2016 campaign and recently published an anti-Trump manifesto in which he accuses his party of enabling the Trump presidency. Trump, in turn, has threatened to spend millions to unseat Flake.


“Great to see that Dr. Kelli Ward is running against Flake Jeff Flake, who is WEAK on borders, crime and a nonfactor in Senate. He's toxic!” Trump tweeted.

Trump aides were taken aback by the tweet. Many of them are deeply skeptical about Ward’s ability to defeat Flake. In 2016, Ward received 39 percent of the vote in an unsuccessful effort to unseat GOP Sen. John McCain. More recently, she came under fire for saying that McCain should step down from the Senate “as quickly as possible” after he was diagnosed with brain cancer.

The White House has met with two other prospective Flake opponents, Arizona state treasurer Jeff DeWit, who was a top official on Trump’s campaign, and former state GOP chairman Robert Graham.

Some in the administration, meanwhile, have set their sights on another Arizona Republican, former GOP Rep. Matt Salmon.

David Bossie, Trump’s former deputy campaign manager and the president of the prominent conservative group Citizens United, has spoken with Salmon, now an official at Arizona State University, about jumping into the contest, according to two people familiar with the talks.

In a brief telephone interview on Thursday afternoon, Salmon said he is currently abroad and not interested in joining the race. He declined to comment on his discussions with Bossie, who did not respond to a request for comment.

People close to DeWit and Graham were also surprised by the Thursday tweet and said the two prospective candidates had been given no advance warning that the president would be weighing in on Ward’s behalf. DeWit and Graham had been waiting for weeks for word from the White House about where the president stood and whom he wanted to support.

It is not the first time that Trump has caught his team off guard on political matters. Last week, the president announced on Twitter that he was endorsing Alabama Sen. Luther Strange in an upcoming special election, a move that directly contradicted the advice of aides who urged him to stay out of the fight, which has pitted establishment Republicans against the conservative base.

The Arizona developments come ahead of a rally Trump is set to hold in Phoenix on Tuesday. White House officials said they expect the president to highlight his opposition to Flake there.

The extent to which he promotes Ward at the event, however, remains unclear. Ward’s aides have made it clear they would like her to speak at the event, though rally organizers declined to say whether she would.

Kelli Ward, a conservative former state senator, has been aggressively positioning herself as a Trump backer. She is running against Sen. Jeff Flake in the Republican Senate primary next year. | Ross D. Franklin/AP Photo

Ward has been aggressively positioning herself as a Trump backer. In recent days, she has hired two operatives who worked on a pro-Trump super PAC, Eric Beach and Brent Lowder, to work on her campaign. On Thursday, she sent out a tweet thanking the president.

“Working hard so you have a conservative from AZ to help #MAGA. Arizonans excited to see you again next week!” she added.

Ward’s aides said they hope to parlay Trump’s tweet into financial backing from his donors. On Thursday, she reached out to Doug Deason, a Texas businessman and the son of billionaire Darwin Deason, though he hasn’t committed. Her campaign announced the support of Bill Doddridge, a major GOP donor and jewelry company executive who funded a Trump 2016 super PAC.

Ward has already received help from Robert Mercer, the reclusive billionaire hedge fund manager who played a critical role in Trump’s 2016 win and remains close to the president. Mercer recently gave $300,000 to a pro-Ward super PAC, and it's possible he will provide more.

Ward also had the support of Mercer in her 2016 campaign, and Breitbart, a pro-Trump website that Mercer funds, published a number of flattering stories about her.

Her backing from Mercer, along with Trump’s Thursday tweet, could chill the interest of other possible Flake primary challengers.

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Trump has long disliked Flake. After the Arizona senator launched a national media tour to promote his book, which administration aides have been reading, the president privately vented about the senator. Before the election, Trump told associates he was willing to spent $10 million out of his own pocket to defeat Flake.

Trump’s move is certain to exacerbate tensions with Senate Majority Leader Mitch McConnell, who has vowed to aggressively defend besieged incumbents like Flake in contested primaries. Flake is expected to receive the support of two McConnell-aligned political organizations, the National Republican Senatorial Committee and the Senate Leadership Fund.