President Joe Biden issued one of his most dire warnings yet that Donald Trump and his allies are a menace to American democracy, declaring Thursday that the former president is more interested in personal power than upholding the nation’s core values and suggesting even mainstream Republicans are complicit.

“The silence is deafening,” he said.

During a speech in Arizona celebrating a library to be built honoring his friend and fierce Trump critic, the late Republican Sen. John McCain, Biden repeated one of his key campaign themes, branding the “Make America Great Again” movement as an existential threat to the U.S. political system. He’s reviving that idea ahead of next year’s presidential race after it buoyed Democrats during last fall’s midterm election, laying out the threat in especially stark terms: “There’s something dangerous happening in America right now.”

“We should all remember, democracies don’t have to die at the end of a rifle,” Biden said. “They can die when people are silent, when they fail to stand up or condemn threats to democracy, when people are willing to give away that which is most precious to them because they feel frustrated, disillusioned, tired, alienated.”