This is the moment the anti-vax movement has been waiting for

Anti-vaccine activists of all political stripes pushed back — hard — against the bill. When they found that inaccurate claims about vaccines didn’t sway California legislators, they shifted gears and asserted that removing nonmedical exemptions impinged on their freedom to raise their children as they wanted. In the late-Tea Party era, that argument had traction.

Renée DiResta, a researcher at Stanford, found through Twitter analysis that there was “an evolution in messaging.” The movement discovered that a focus on freedom “was more resonant with legislators and would help them actually achieve their political goals,” Ms. DiResta said to me. Anti-vaccine Twitter accounts that had been posting for years about autism and toxins pivoted to Tea Party-esque ideas, leading to the emergence of a new cluster of accounts focused on “vaccine choice” messaging, Ms. DiResta said…

With vaccine refusal reframed as “parent choice,” Republicans could no longer risk appearing to oppose “freedom of choice” on any issue. More state anti-vaccine PACs and nonprofit groups formed, and social media allowed greater collaboration. The “freedom” messaging united anti-vaccine groups, particularly those in Texas and California, and withstood social media platforms’ growing attempts to stanch false claims.