West Virginia Democratic Sen. Joe Manchin split with his party Friday, vowing to support Brett Kavanaugh's nomination to the Supreme Court.

The stunning break with his fellow Senate Democrats comes after weeks of indecision by Manchin. Hours after reviewing an FBI report on sexual assault allegations against Kavanaugh, Manchin voted to advance the nomination.

But Manchin remained mum on his final decision until he knew where all of his colleagues stood. The Senate is expected to hold its final vote on Kavanaugh's nomination on Saturday.

[Click here for complete Kavanaugh coverage]

"I have reservations about this vote given the serious accusations against Judge Kavanaugh and the temperament he displayed in the hearing," Manchin said. "And my heart goes out to anyone who has experienced any type of sexual assault in their life. However, based on all of the information I have available to me, including the recently completed FBI report, I have found Judge Kavanaugh to be a qualified jurist who will follow the Constitution and determine cases based on the legal findings before him. I do hope that Judge Kavanaugh will not allow the partisan nature this process took to follow him onto the court."

Though Manchin left himself room to oppose Kavanaugh early on over his concern on how the nominee would rule on pre-existing conditions, the centrist Democrat ultimately sided with Republicans.

“With respect to any cases that may come before him impacting the 800,000 West Virginians with pre-existing conditions, Judge Kavanaugh assured me personally that he would consider the human impacts and approach any decision with surgical precision to avoid unintended consequences," Manchin said.

[Read: Susan Collins says 'yes': Kavanaugh set for Supreme Court]

Manchin kept in close contact with fellow moderates Democrat Heidi Heitkamp of North Dakota and Republican Sens. Susan Collins of Maine and Lisa Murkowski of Alaska throughout the process.

Heitkamp's decision to vote against Kavanaugh surprised Manchin, but he said it wouldn't influence him.

"Heidi made her decision; I'll make mine," he said Thursday.

Then on Friday, Manchin said he "voted to confirm Judge Kavanaugh’s nomination to serve on the Supreme Court because I believe he will rule in a manner that is consistent with our Constitution."

Manchin is facing a tough reelection in November in a state President Trump won by 42 points, but the Democrat has a solid lead in most polling.