Hillary Clinton attack dog David Brock is desperate to cling to power in the progressive movement, and so he has issued an open letter to Vermont Sen. Bernie Sanders apologizing for his dirty actions during the presidential campaign.

“Looking back, I recognize that there were a few moments when my drive to put Hillary in the White House led me to take too stiff a jab. I own up to that, I regret it, and I apologize to you and your supporters for it,” Brock, who operated the pro-Clinton super PAC Correct the Record, wrote in a letter on Medium.

During the Democratic primaries, Brock did the dirty work that the Clinton campaign largely avoided by going after Sanders’ health and by comparing him to various radical leftists.

Brock, a former Clinton critic who had a change of heart in the 2000s, now hopes to partner with the progressive Sanders to combat Donald Trump. The suck-up to Sanders most likely a response to the fact that Clinton’s stock in the Democratic party is in free-fall status following her Election Day loss.

“The progressive movement is strong and growing, thanks in large part to your candidacy, Senator Sanders, which electrified so many voters,” wrote Brock, who operates the groups Media Matters, American Bridge, and Shareblue.

“The bedrock American values you championed — of pluralism, equality, and opportunity – are ones I share. And I hope that we can be partners in the fight ahead.”

Brock’s actions against Sanders in the campaign were criticized by Clinton’s top campaign officials. Campaign chairman John Podesta slammed Brock in emails that were stolen from his Gmail account and published by WikiLeaks.

During the campaign, Brock refused repeated calls to apologize to Sanders. And one former Brock employee is now criticizing the operative for the about-face. At one point, Sanders referred to the Clinton hatchet man as “the scum of the earth.” (RELATED: Clinton Minion Won’t Apologize For Dirty Attack On Bernie Sanders)

William Urquhart, a former video tracker at the Brock-controlled American Bridge, said that employees of the firm had their jobs threatened for questioning attacks against Sanders.

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