Updated at 9:30 p.m.

West Virginia Gov. Jim Justice announced he will flip from the Democratic Party to the GOP, making the announcement Thursday night while appearing at a Trump campaign with the president.

"Today I will tell you with lots of prayers and lots of thinking, I'll tell you West Virginians, I can't help you any more being a Democrat governor," Justice said.

"The Democrats walked away from me," the governor argued, and reflected that his late mother, who was a big fan of former President Ronald Reagan, was looking down on him thinking, "Jimmy, it's about damn time you came to your senses."

Trump had teased "a very big announcement" during the Huntington, W.Va., rally and the New York Times was first to report that Justice's party switch would be the major reveal.

First elected last November as a conservative Democrat, Justice is a billionaire coal and real estate businessman who has drawn comparisons to Trump. He's identified as a Republican and an independent in the past, and he declined to endorse Democratic presidential nominee Hillary Clinton in 2016.

On Thursday, Justice enthusiastically threw his support behind the president, saying he had already visited him at the Oval Office to talk about coal and manufacturing jobs. He praised Trump's children, noting he's gone hunting with his sons, and said, like him, the president isn't a politician.

"This man is a good man," Justice said. "He's got a backbone. He's got real ideas. He cares about America. He cares about us in West Virginia."

Trump heralded Justice's decision as evidence that "our agenda rises above left or right."

Justice's switch means Republicans now have control of a record 34 governorships — tying a record set nearly a century ago in 1922 — and gives the GOP complete control of state government in 26 states.

The last high-profile party-switch — Pennsylvania Sen. Arlen Specter's 2009 flip from Republican to Democrat — was the result of a lengthy courtship process from top-level Democrats. That wasn't the case here.

West Virginia Republicans were caught completely off-guard. Underscoring that fact: state Republican Chairman Conrad Lucas was out of the country on his honeymoon when the party learned of Justice's decision.

"We are very cognizant of the fact that we have criticized him greatly in the past for his various policy positions and the way he has conducted his businesses," Lucas told NPR. "However all that conduct was done while he was a Democrat. Today he's a Republican so we look forward to moving forward."

Indeed, West Virginia Republicans were criticizing Justice as recently as earlier Thursday, when the party tweeted out a story critical of him.

At the time of the switch, the state party website was filled with anti-Justice press releases and posts. "The ethical problems of this administration will soon become obvious," the state GOP said in a press release just a few weeks ago.

In February, they called Justice a "deadbeat" for still owing $4.4 million in back taxes.

Lucas still sounded a bit wary Thursday night. "We will treat him as a member of our party, but we expect him to act as a member of our party," he said.

But national Republicans cheered the move. Republican Governors Association Chairman and Wisconsin Gov. Scott Walker said in a statement that "we're thrilled that Governor Jim Justice wants to join our efforts. On behalf of our nation's Republican governors, we welcome Governor Justice to the RGA, and look forward to working with him to advance conservative principles and strengthen West Virginia."

However, national Democrats — who were not informed about Justice's decision before the news leaked — were quick to point out that Republicans spent plenty of time attacking Justice when he was their opponent. Ahead of the announcement, the West Virginia Republican Party's website was headlined by multiple anti-Justice posts.

"Jim Justice deceived the voters of West Virginia when he ran as a Democrat 8 months ago," Democratic Governors Association Executive Director Elisabeth Pearson said in a statement. "West Virginians have learned that they simply can't trust Jim Justice. He will always put his financial interests above the needs of West Virginians.

"As Republicans have repeatedly said, Jim Justice owes millions of dollars in unpaid company taxes, after a deal with a Russian coal company," Pearson continued. "The debts have only worsened during Justice's term as governor. If President Trump cut a deal, we hope it does not put U.S. taxpayers on the hook to bail out Jim Justice's personal finances."

While the Mountaineer State has been historically Democratic, the state has moved to the right on the federal level, especially in recent years. West Virginia gave Trump one of his largest margins of victory in November, winning the state by almost 42 points.

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