The GOP runoff for governor is no longer a contest 'twixt Casey Cagle and Brian Kemp.

It has become a tug-of-war featuring the two most popular Republicans in the state of Georgia: Gov. Nathan Deal and President Donald Trump, who have placed themselves on opposite sides of Tuesday’s finale.

The two hairpin turns came in the last days of a bitter, nine-week feud, one endorsement on top of the other. Which voice Republican voters listen to could determine the direction of the Georgia GOP for years to come.

Let’s start with Governor Deal, who was required to insert himself when his preferred candidate became mired in a series of headlines erupting from the piecemealed release of a secretly recorded conversation with former rival Clay Tippins.

On Monday, Deal made clear that his endorsement of Cagle was more about policy than personality. The governor pointed to the economic gains made during his eight years in office.

“My concern is, let’s not undo or transform, in a negative fashion, the good reforms that have been put in place. And that will be the challenge for the next governor of this state — is to not go backwards, but to go forward,” he said.

In essence, the governor’s endorsement of the lieutenant governor was a defense of Dealism. Which I would argue has two important facets:

-- Over the last eight years, when asked to choose between economic concerns and the worries of social conservatives, the governor has given greater weight to job creation. The rule is not a hard-and-fast one. Deal did sign legislation to permit concealed firearms on the campuses of public universities. Call it a guideline that served as the basis for the governor’s rejection of attempts to give legal protection to religious conservatives who don’t want to do business with same-sex couples.

-- The second tenet of Dealism is the maintenance of a party identity that is separate from Republicans who frequent the District of Columbia. A Georgia Republican isn’t quite the same thing as a Washington Republican. The practice has its roots in the traditions of a Georgia Democratic party that once claimed Deal as a member — but it has offered this GOP governor a path around the gridlock that has paralyzed the nation’s capital.

President Donald Trump on Wednesday tweeted his "full and total endorsement" for Secretary of State Brian Kemp in the state's Republican race for governor.

Lurking behind both pillars of Dealism is a recognition that the days of ruling Georgia through the prism of a hardcore Republican primary won't last forever. Stacey Abrams, the Democratic nominee for governor, may be part of that calculation. A $1 million donation from billionaire George Soros to the Democratic Party of Georgia speaks loudly, too.

The day after Trump chose his opponent as the favorite, one of Cagle’s first responses was to raise the issue of electability — and question the straying from Georgia Republicanism. “Many of the insiders in Washington D.C. may have misled him,” the lieutenant governor said of Trump. “And clearly, we’re the only candidate that can win in November.”

But November vulnerability had no place in the endorsement by President Donald Trump.

“Brian Kemp is running for Governor of the great state of Georgia,” the president tweeted, only 48 hours after Deal made his pick. “Brian is tough on crime, strong on the border and illegal immigration. He loves our Military and our Vets and protects our Second Amendment. I give him my full and total endorsement.”

Since the May primary, both Kemp and Cagle have attempted to present themselves as clones of Trump, but it is Kemp who has conducted the more Trump-like campaign — relying on increased turnout within a traditional, white Republican base rather than overtures to independents.

In the summer heat, it hasn’t been a bad strategy. With brash TV displays of his guns, his pick-up truck, and promises to round up “criminal aliens” and remain “politically incorrect,” Kemp has vaulted from a distant second to frontrunner.

In his 2016 campaign, Trump rode to victory with a slogan laden with subtext: “Make America Great Again.” Kemp has the equivalent, constantly referencing his dedication to “hardworking Georgians.” Who are surely all Republican.

In other words, Trump’s entry into the race for governor is a boost to those seeking to align the Georgia Republican party more closely — tactically and philosophically — with the national organization that the president is in the process of re-creating.

That may not be good for Georgia business interests now pushing for an expanded draw-down of federal Medicaid dollars to help rescue health care in south Georgia. (Cagle has left the door cracked on the issue, while Kemp has slammed it shut.)

Despite Cagle’s promise to back such legislation, opponents of “religious liberty” legislation may have more to fear in a Trump-driven Georgia GOP. If his presidency has taught us anything, it’s that Trump puts a high value on cultural warfare.

But a Trump-aligned Georgia GOP could also benefit many who currently have access to the White House and the president inside. Ralph Reed, for instance, who was defeated by Cagle in a 2006 GOP bid for lieutenant governor. Reed now helps keep white evangelical voters in the Trump camp.

And there are the Perdue cousins.

U.S. Sen. David Perdue may be Trump’s staunchest defender in the Senate. Former Gov. Sonny Perdue, now the U.S. secretary of agriculture, was in a cabinet meeting with the president that adjourned only hours before Trump issued his endorsement of Kemp.

Both deny involvement in Trump’s decision to back Kemp, but some Republicans aren’t buying. “I’m betting President Trump wouldn’t know his pick for Georgia Governor if he got in a cab with him or pick him out of a 2 person photo line up! Makes you wonder [where] it came from,” wrote former congressman Lynn Westmoreland via Twitter. (He’s a Cagle supporter.)

Hours later, Westmoreland was more specific. “Sonny, he was the king of the Georgia Republican Party there for a while,” Westmoreland said. “And if he can play in this governor’s race then he’ll stay that way.”

And Dealism would give way to the return of Perdue-ism.