Donald Trump said in a Truth Social post that Sen. Joe Manchin had gone "off the rails."
He commented that Manchin should have joined the GOP "long ago."
Manchin was invited by Senate Minority Leader Mitch McConnell to switch sides last December.
Former President Donald Trump suggested on Wednesday that Sen. Joe Manchin should have been brought into the GOP fold "long ago."
In a post on Truth Social, Trump lashed out at Senate Minority Leader Mitch McConnell, whom he has been feuding with for months.
Trump wrote that McConnell had played his cards wrong where Manchin, a moderate Democrat, was concerned.
The West Virginia senator has been a stumbling block to the Democratic majority passing legislation in the Senate. One of the most prominent examples was when he gutted President Joe Biden's "Build Back Better" spending plan.
However, Manchin has also been instrumental in helping the Democrats move legislation like the Inflation Reduction Act through the Senate.
"When people ask, 'What happened to Joe Manchin, why did he go off the rails?' The answer is very simple - Mitch McConnell forced his hand by saying that Manchin was weak and ineffective and that he, McConnell, had him totally under control," Trump theorized in his post.
"Manchin couldn't stand for that and turned strongly, not against the Republicans, but against McConnell, who he has always despised," the former president added.
"The fact is, Joe Manchin should have been brought into the Republican Party long ago," Trump wrote.
Representatives for Manchin did not immediately respond to a request for comment from Insider.
The former president's comments came after Manchin's push to make it easier to build fossil fuel projects was slapped down in the Senate by the Democrats' liberal wing of the Senate Democrats and the Senate GOP.
At a press conference on Tuesday, Manchin griped about the odd alliance of Bernie Sanders-fronted Democrats and the GOP.
"I've been around a long time in state politics and federal politics," Manchin said. "I've never seen stranger bedfellows than Bernie Sanders and the extreme liberal left siding up with the Republican leadership in the caucus."
"What I'm hearing is that this is like revenge politics. Basically revenge towards one person, me," he added.
However, Trump is incorrect about McConnell not having attempted to make nice with Manchin. In December, McConnell invited Manchin to join the GOP and slammed the Democratic Party for calling Manchin a "liar." McConnell also accused the party of wanting to "embarrass" Manchin.
"Obviously, we would love to have him on our team," McConnell told The New York Times in December. "I think he'd be more comfortable."