A conservative Democratic senator who has frequently butted heads with President Biden and the rest of his party, Joe Machin, told a radio interviewer in his home state of West Virginia Thursday that he is considering leaving the party and striking out on his own.

In an appearance on “Talkline” on MetroNews, Mr. Manchin told host Hoppy Kercheval that he has not made a final decision but said the increasing extremism in both national parties is nudging him in that direction. He said he is seriously considering becoming an independent, much like another maverick senator, Kyrsten Sinema of Arizona, did late last year.

“I’ve been thinking about that for quite some time,” Mr. Manchin said. “I haven’t made any decisions whatsoever on any of my political directions. I want to make sure that my voice is truly an independent voice. When I do speak, I want to be able to speak honestly about basically the extremes of the Democrat and Republican Party that’s harming our nation.”

He added that the current Democratic “brand,” as he put it, is tarnished and out of touch with the bulk of his constituents. “The brand has become so bad, the D brand and R brand,” he said. “It’s not the Democrats in West Virginia, it’s the Democrats in Washington.”

Mr. Manchin has been at loggerheads with his Democratic colleagues in the Senate, as well as the Biden administration, for much of Mr. Biden’s tenure. The conflict began shortly after he helped the president get his $1.2 trillion 2022 green energy legislation, dubbed the Inflation Reduction Act, over the hump in the Senate.

While he initially praised the act as “one of the most historic pieces of legislation passed in decades,” he later soured on its implementation and railed against what he said is the administration’s “radical climate agenda” driving its rollout. He has threatened to repeal the measure if given the chance, and has been holding up a number of Biden appointments to the Environmental Protection Agency in protest.

Mr. Manchin, who faces a tough re-election contest next year and is trailing his likely Republican opponent, Jim Justice, badly in the polls, has reportedly been courted by the No Labels political movement to run a third-party campaign in next year’s presidential election. Democrats are terrified that such a contest would peel away enough votes from Mr. Biden to hand the election to President Trump if he secures the nomination.

Mr. Manchin expressed skepticism about that analysis in Thursday’s interview. “I don’t see that favoring either side, because you just can’t tell how this is going to break,” he said of the No Labels effort. “If, come January and February of next year, these are still the main contenders, Donald Trump and Joe Biden, that’s a whole other scenario. If they are not — and it could break between now and then — that changes the game completely.”

In the interview, Mr. Manchin was as contemptuous of the Republican Party as he was of his own. Both parties have gone “off the Richter scale,” he said, with moderate Republicans left homeless by the current GOP’s extremism and idolization of Mr. Trump, and moderate Democrats alienated by a fiscally irresponsible national party obsessed with left-wing social causes.  

“If we can create a movement, Hoppy, that people understand, we could have a voice,” Mr. Manchin said. “We could make a big, big splash, and maybe bring the traditional parties of the Democratic and Republican Party [back to] what they used to be, back to what they should be.”