Thursday night’s blockbuster story in The New York Times—which reported that President Donald Trump ordered special counsel Robert Mueller fired last June but backed down when White House counsel Don McGahn threatened to resign—confirms just how terrified the commander-in-chief is of the Russia investigation. But if Trump pulled back from the full constitutional crisis that firing Mueller would have sparked, he and his allies in the Republican Party have pursued an almost equally dangerous plan B: If they can’t fire Mueller, they can at least discredit the investigation so that GOP partisans will reject the findings and stay loyal to the president and his party.

To that end, Trump, much of the right-wing media, and a cohort of congressional Republicans have been loudly talking about an alleged “deep-state” conspiracy rooted in the Department of Justice and a “secret society” embedded in the FBI that are both resoundingly focused on taking down the president. These theories, often echoed on Fox News and by the president’s tweets, have only the flimsiest basis in reality: The phrase “secret society” was used as an obvious joke in a text exchange between two FBI agents after the 2016 election.

Yet prominent Republicans are willing to treat that jest as though it referred to an actual organization. “It’s more than bias, but corruption at the highest levels of the FBI and that secret society,” Senator Ron Johnson of Wisconsin told Fox News on Tuesday. “We have an informant that is talking about a group that were holding secret meetings off-site. There is so much smoke here, there is so much suspicion.” (The following day, Johnson retreated from those remarks.)

On Tuesday night, Sean Hannity went into full tinfoil-hat mode, declaiming that the plot against Trump is nothing short of staggering:

This ... is so much bigger than Watergate. It’s about our Constitution, about the rule of law. It has been shredded. All because powerful people at the highest level in the DOJ and the FBI thought they knew better than you as to who should be president. There needs to be serious ramifications if we are going to save our country in all of this. People must be held accountable, they must be investigated, they must be indicted, and probably many of them thrown in jail.

The paranoid ravings of Johnson, Hannity, and indeed Trump himself have a familiar lilt: They echo the venerable tradition of conspiracy theories that has flared up again and again in U.S. history, from the fear of the Bavarian Illuminati in the 1790s to the anti-Masonic fervor of the 1820s to the anti-Catholic scare of the mid-19th century to the anti-communist crusade of the 1950s.