hen an ideological extreme faction with unpopular views emerges, it becomes a threat to the party that hosts it. At first, the party’s incentive is to banish the extremists, lest their toxic ideas taint the party’s brand with the broader electorate. But if the radical faction’s growth is not arrested, the calculus changes, and barring the doors can no longer work. It forms a large enough part of the base that the party can’t afford to alienate its members. The crank wing becomes too big to fail.

I believe the anti-vaccine movement is reaching that point in the Republican Party. The movement’s position is akin to the tea party in 2009, or the birther movement a few years later — perhaps (this is a rough estimate) smaller than the former but larger than the latter. The cause has too many adherents, who supply too much energy, for the party to risk alienating…

One indication of the anti-vaxx movement’s rise is through the explosive growth of anti-vaccination media personalities like Joe Rogan and Alex Berenson, who have forced established conservative pundits to co-opt their appeal. The Fox News prime-time lineup is creeping farther and farther right on vaccines. Sean Hannity recently declared, “Now that we know that whether you’re vaccinated or boosted and had natural immunity you’re still going to get it, why is he still calling it a ‘pandemic of the vaccinated’?” Laura Ingraham claimed “vaccines aren’t stopping the spread from people from getting sick, so when can we end this ‘mandates work’ charade?”