Steve Schmidt warned that President Donald Trump was undoing centuries of American progress and gathering authoritarian powers.
The former Republican strategist appeared Tuesday on MSNBC's "Morning Joe" to explain why he left the GOP last week.
"There is only one requirement now to be labelled a conservative in good standing -- absolute, total obedience to Trump," Schmidt said.
Republicans continue to follow Trump through a "blizzard of lies," which he uses to scapegoat and demonize the vulnerable through conspiracy theories.
"It doesn't matter what he says, and so in the 240th year in the independence of the United States, in three states by 78,000 votes, the American people by a fluke elected an imbecilic former reality TV show host and con man whose only affinity for reading anything were the Adolf Hitler speeches he kept on his nightstand," he continued.
He said the "American century" was coming to an end, and he placed the blame on Trump and his GOP allies.
"America's decline is beginning and we should make no mistake about this," Schmidt said. "The U.S.-led liberal global order is in peril, it's in threat. Will he take us out of the World Trade Organization? Will he undermine the international system that Franklin Roosevelt conceived, that Harry Truman built, that was sustained through Ronald Reagan and Barack Obama?"
"It's anyone's guess, but the idea that tomorrow will be okay because yesterday was or last year was is a naive view of the world," he added.