Sen. Richard Shelby, R-Ala., said he had to cast his vote for a Republican — but it was not Roy Moore "because the state of Alabama deserves better" and he reached his "tipping point" — adding he did not believe President Donald Trump's endorsement will be the deciding factor in Tuesday's special election.

"I'd rather see the Republican win, but I would hope that Republican would be a write-in," Sen. Shelby told CNN's "State of the Union." "I couldn't vote for Roy Moore. I didn't vote for Roy Moore. But I wrote in a distinguished Republican name.

"I'd rather see another Republican in there, and I'm going to stay with that story. I'm not going to vote for the Democrat, I didn't vote for the Democrat or advocate for the Democrat. But I couldn't vote for Roy Moore. The state of Alabama deserves better."

Unlike President Trump, Shelby could not back Moore amid the myriad allegations of sexual misconduct, despite a shared desire to maintain the Republican Party's narrow 52-48 majority in the U.S. Senate.

"I understand where the president's coming from," Shelby added to host Jake Tapper. "I understand we would like to retain that seat in the U.S. Senate. But I tell you what, there's a time, we call it a tipping point, and I think so many accusations, so many cuts, so many drip, drip, drip, when it got to the 14-year-old's story, that was enough for me. I said, I can't vote for Roy Moore."

Shelby added President Trump's endorsement is not going to sway Alabama's voters anyway.

"I think Roy Moore has his own following regardless of whether the president's involved or others," Shelby told Tapper. "I don't know what's going to happen Tuesday. It depends on the turnout, and go from there. But I do believe, and I'm going to say it again, the Republicans could do better.

". . . The state of Alabama deserves better. I think we've got a lot of great Republicans that could've won and carried the state beautifully and served honorably."