Democrats praised Sen. Bernie Sanders last year as a “team player” for his efforts to help his former primary rival Joe Biden win the presidency. But in recent days, the Vermont socialist has become increasingly caustic in criticism of his centrist Democratic colleagues in the Senate.

Sanders faced criticism in 2016 for what some Democrats saw as a refusal to concede to Hillary Clinton and dragging out a brutal primary — but he won praise from Democrats for actively supporting Biden in 2020.