After endorsing Hillary Clinton and urging his supporters to do the same at the Democratic National Convention earlier this week, Sen. Bernie Sanders (I-VT) has officially left the Democratic Party.

“And now, despite pleading with his base to support Hillary, even though they’re concerned that she’s too moderate, Sanders will return to Vermont and to his seat in the Senate, and he’ll do it with no official party affiliation,” writes Heatst.com reporter Emily Zanotti.

Sanders has reportedly identified as a socialist — left of the Democratic Party — since entering politics in 1979 except for when he declared his presidential campaign in 2015 and affiliated with the Democratic Party.