Democratic Sen. Joe Manchin of West Virginia announced Friday he has registered as an independent, raising questions about his future political plans.

Manchin, who would have faced a tough reelection in November if he had chosen to run, has long been an outspoken critic of the Democratic Party and an obstacle to many of President Joe Biden's legislative priorities.

He said in a statement that over the last 15 years he has seen both major political parties leave their constituents "behind for partisan extremism while jeopardizing our democracy."

But his announcement left many questions unanswered. Manchin did not disclose if he will continue caucusing with Democrats in the Senate, where they hold a slim majority. And he did not indicate if he will be running for higher office in the near future.

A request for further comment from his office was not immediately returned.