Generation Forward, the super PAC established to support former Maryland Gov. Martin O’Malley’s bid for the Democratic nomination for president, is attacking Vermont Sen. Bernie Sanders for his support of gun rights. This comes just as Sanders, who declared his candidacy in late May, appears to be gaining ground against the still-prohibitive frontrunner, Hillary Clinton.

Sanders, a self-described socialist, represents a rural state whose laws have long been very supportive of gun ownership. With Democratic politicians looking for a legislative outlet for the outrage over last week’s racist, terrorist murders of nine people at a black church in Charleston, it’s only natural that gun control is making an early appearance in the party’s presidential primaries.