Democratic activist David Brock has been exposed as one of the key sources of money behind efforts during the 2016 presidential campaign to entice women to accuse Donald Trump of past sexual misconduct.

It was only the latest caper for Brock, who spent the 1990s attacking the Clintons before undergoing a political conversion, and devoting his efforts — and other people’s money — to a crusade to destroy Republicans and the conservative media.

Brock founded Media Matters for America in 2004. Billed as a “charity” — and exempted from taxes — the group theoretically corrects conservative bias in the media. In practice, Media Matters attempts to eliminate conservative perspectives altogether, targeting popular hosts, journalists, and outlets. The organization also routinely promotes left-wing causes: in 2011, for example, Media Matters aligned with the radical Occupy Wall Street movement.

Despite the group’s political agenda, mainstream media outlets routinely rely on Media Matters for talking points. Recently, for example, CNN’s Chris Cuomo admitted on the air that he relied on material from Media Matters in criticizing Breitbart.

The zenith of the group’s influence was in the 2008 presidential elections, when mainstream media worked in concert to elect Barack Obama, and to avoid and discourage efforts to probe his views and record.

In advance of the 2012 election, Media Matters drew up a plan, Project 2012, which aimed to destroy opposition media sources, especially Fox News, Rush Limbaugh, and Breitbart. One part of the plan, “litigation,” proposed to “[b]ring litigation against Fox News and its feeders holding them accountable for illegal and tortious actions.” The document explained that lawsuits were needed because the federal government was “reluctant to police the media.”

Brock has also entered the political arena through his super PAC, American Bridge 21st Century, which he started in 2010, to conduct opposition research against Republicans. The group is backed by left-wing billionaire George Soros, who has been involved in Brock’s other efforts.

Emails released by Wikileaks in 2016 raised questions about whether American Bridge and other pro-Clinton super PACs were coordinating improperly with the campaign.

Since the 2016 elections, Brock has quarterbacked efforts by Democratic organizations to impeach the president, as described in a confidential memo obtained by the Washington Free Beacon last January. He has also talked about creating a “Breitbart of the left” in the media.

But some Democrats are already tired of his antics. Paying women to attack Donald Trump is just the latest example of how Brock is willing to debase his cause to defeat his enemies.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He was named to Forward’s 50 “most influential” Jews in 2017. He is the co-author of How Trump Won: The Inside Story of a Revolution, is available from Regnery. Follow him on Twitter at @joelpollak.