WASHINGTON (AP) — Competing in a contested runoff campaign for Georgia's governor, Brian Kemp didn't see it coming: the single-most prized endorsement in Republican politics.

When President Donald Trump tweeted his support last week of Kemp over his Republican opponent, Lt. Gov. Casey Cagle, the Georgia secretary of state was holding a news conference announcing an endorsement from a former primary rival. Kemp had no warning that the president would deliver his "full and total endorsement."

The endorsement ahead of Tuesday's runoff was the latest example of how Trump has become more emboldened in offering his imprimatur on a number of Republican contests — despite being burned in a bitter Alabama Senate campaign last year.

Three Trump administration officials said Trump endorsed Kemp after conferring with Agriculture Secretary Sonny Perdue, a former Georgia governor who officials said circumvented the internal process on endorsements to advocate on Kemp's behalf. The officials spoke on condition of anonymity to discuss internal deliberations. A representative for Perdue didn't respond to a request for comment.

Trump has also been inclined to endorse Kansas Secretary of State Kris Kobach for governor ahead of the state's Aug. 7 primary, two of the administration officials said. But aides have warned the president that it would alienate Republicans loyal to Kansas Gov. Jeff Colyer, who succeeded Sam Brownback when Trump selected him for a diplomatic post.

Last spring, Trump was on the verge of tweeting out an endorsement of Kobach but his staff intervened, warning of the repercussions, the officials said. But they said Trump may still endorse Kobach anyway.

The political maneuvering puts the president at risk of being on the losing side of a Republican race, as he was in Alabama last year when he initially supported Sen. Luther Strange, who lost a Republican primary to Roy Moore. Trump then urged voters to support Moore in the general election, even after the former judge was stung by multiple allegations of sexual misconduct. Moore lost the race to Democrat Doug Jones.

"When he creates bad blood is when he splits with the establishment and makes the job holding the seat more difficult. Alabama is the best example of that," said Alex Conant, a Republican strategist. However, he said, "for the most part, when Trump has endorsed a candidate it's strategic and it helps the likelihood that we'll keep the seat."

Despite the potential downside, Trump has stitched together a winning streak in Republican races that could benefit him in the months ahead.

Trump's willingness to serve as a kingmaker in Republican contests has allowed him to demand more loyalty within a party that once openly considered abandoning him during the final weeks of the 2016 campaign. And it has also been another tool to strengthen his base of supporters, who have followed his lead when he decides to make clear his preferences.

The results of late have been to his liking.

During a contentious West Virginia Senate primary, Trump heeded the call of Republicans by using his Twitter feed to urge Republican voters not to support Don Blankenship, the ex-coal executive who spent a year in federal prison for violating safety regulations in a deadly 2010 mine explosion.

West Virginia's attorney general, Patrick Morrisey, won the primary, giving Republicans a shot at defeating Democratic Sen. Joe Manchin in one of the top Senate battlegrounds.

In South Carolina, Trump used a last-minute endorsement of state Rep. Katie Arrington to help oust Mark Sanford, a Republican congressman who had criticized the president. Trump also staged a rally on behalf of South Carolina Gov. Henry McMaster, who was among the first elected officials to publicly embrace Trump during his 2016 campaign. McMaster fended off his Republican opponent.

And last week in Alabama, Trump tweeted out an endorsement of Rep. Martha Roby, a Republican who was facing a runoff against Bobby Bright, a one-time Democratic congressman. Roby easily dispatched Bright, who had tried to capitalize on Roby's decision to distance herself from Trump after the "Access Hollywood" tape during the 2016 fall campaign.

Roby has since sought to make amends with Trump, who triumphantly tweeted that his endorsement opened the "flood gates," adding, "and you had the kind of landslide victory that you deserve."

In Florida, Trump is expected to rally Republicans next week on behalf of Gov. Rick Scott, who is running for Senate, and Rep. Ron DeSantis, a candidate for governor who faces Adam Putnam, the state's agriculture commissioner, in the party primary.

"Die-hard Putnam supporters would wish the president wouldn't endorse. But at the end of the day whoever wins that primary will unite Florida Republicans," said Tom Reynolds, former New York congressman and head of the GOP's congressional fundraising arm.

In Georgia, Trump's endorsement of Kemp came on the heels of Cagle's endorsement by Republican Gov. Nathan Deal and the National Rifle Association, a key Trump constituency. But a White House official said officials raised concerns about Cagle's viability in the general election when they reviewed polling after the emergence of an audio recording in which Cagle is heard explaining he engaged in political maneuvering for a "bad public policy" bill for a tax credit scholarships program.

Vice President Mike Pence, who led a rally on Kemp's behalf Saturday, was among the White House officials who spoke to Trump about the Kemp endorsement, the White House official said. Pence's chief of staff, Nick Ayers, is a former Georgia political consultant who served as a top strategist to Perdue. The official said Ayers was among a group of aides who raised concerns about Cagle's viability but was not a deciding factor in Trump's endorsement.

"As you know, we had the momentum going into the final stretch," Kemp said during Saturday's rally with Pence. "But their support has created what we are now calling the 'Kemp surge.'"

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