The president endorsed the gubernatorial candidate who promised to “round up criminal illegal” immigrants in his own pickup truck. Photo: Kemp for Governor via YouTube

Typically Donald Trump’s interventions in Republican primaries have been relatively predictable, based on rewarding loyal supporters (Henry McMaster), punishing rebels (Mark Sanford), or listening to party pooh-bahs who think a disfavored candidate could cost the GOP a key congressional seat (Roy Moore, Michael Grimm).

But POTUS’s “full and total endorsement” of the gubernatorial candidacy of Georgia secretary of state Brian Kemp, tweeted out yesterday afternoon, was something of a bolt from the blue, even to his beneficiary, as the Atlanta Journal-Constitution reports:

Kemp seemed to be caught off-guard by the timing. The president’s tweet Wednesday afternoon came as the secretary of state was in the middle of a press conference with Clay Tippins, the former GOP candidate who stirred up the race with his secret recording of the lieutenant governor.

Kemp said when he looked up to see ecstatic aides eyeing their cellphones and “jumping up and down,” he knew something was up.

Kemp has been no more conspicuously adulatory toward Trump than his July 24 GOP runoff opponent, Lieutenant Governor Casey Cagle. And while some Republicans worry that Cagle’s history of ethics allegations could affect a general-election candidacy against nationally renowned Democrat Stacey Abrams, Kemp’s got his own ethics issues.

The Journal-Constitution may have best explained Trump’s intervention as the product of old alliances: Kemp was first appointed secretary of state by former governor and now U.S. Agriculture Secretary Sonny Perdue, whose cousin and political ally Senator David Perdue is one of Trump’s most loyal lieutenants in the Senate. Both Perdues are also close to Nick Ayers, who is Mike Pence’s chief of staff.

However it transpired, Trump’s political allies are responding quickly. Former House Speaker Newt Gingrich, whose fame has never faded in his original stomping grounds, has quickly climbed aboard the Kemp bandwagon. And more importantly, Pence is now planning a trip to Georgia this weekend to thump the tubs for Kemp, just before Tuesday’s balloting.

Team Trump’s intervention puts him on a collision course with a Georgia Republican whose intraparty popularity rivals POTUS’s: two-term incumbent governor, Nathan Deal, who endorsed Cagle earlier this week after many months of neutrality in the race to succeed him. As Greg Bluestein explains, Deal is leaving office with enviable popularity:

A pair of Atlanta Journal-Constitution/Channel 2 Action News polls earlier this year showed why Deal’s help was so coveted. One showed roughly half of Democrats approve of the way he’s handled his job as governor. In a separate poll of Republicans, a whopping 85 percent gave him positive reviews.

That makes him far more popular than President Donald Trump, who earned an 80 percent approval rating from Republicans — and only about 7 percent from Democrats. And Deal is towering over institutions such as Congress and the state Legislature.

In a sign of the competitive atmosphere that led Cagle to complain (in a secretly taped conversation later leaked by Kemp) that the primary had become a test of “who could be the craziest,” both runoff candidates ran to the right of Deal, which is probably why it took a while for the incumbent to back the man who served as lieutenant governor throughout his administration, and who is even from the same North Georgia town. It’s now anybody’s guess about the outcome, though Kemp has in a couple of recent polls finally caught up and perhaps moved past Cagle, who has been the front-runner from the get-go, receiving 39 percent in the May primary. The dueling endorsements occurred near the end of the early voting period, which began on July 2. And Cagle has his own wing-nut street cred, with NRA president Oliver North campaigning on his behalf.

From a national perspective, Trump has aligned himself with a candidate who has earned enduring fame for his savagely right-wing campaign ads (the subtext of Cagle’s complaint about craziness). This ad just before the primary was an instant classic:

His final ad features Trump, of course, but he also reminds viewers he is a “politically incorrect conservative.”

Kemp’s not just a right-wing show horse, though: As Georgia’s chief election official, he’s been a big-time voter suppressor.

If Trump buys Cagle’s hypothesis that GOP primaries are about craziness, he’s picked the right horse in Georgia.