David Hogg, the gun control activist who serves as a vice chair for the Democratic National Convention, is feuding with Democratic Party officials as he seeks to primary candidates.

Hogg has vowed to spend millions of dollars seeking to replace establishment Democrats in primary races, asserting that they are insufficiently combating President Donald Trump. The decision earned him criticism from Democratic National Committee Chair Ken Martin, who said that Democratic Party officials “can’t be both the referee and also the player at the same time.”

“If you want to challenge incumbents, you’re more than free to do that, but just not as an officer of the DNC, because our job is to be neutral arbiters,” Martin remarked on a media call. “This is not about shielding incumbents or boosting challengers. It’s about voters’ trust in the party.”