It isn’t quite what you’ve italicized, but make no mistake that’s it’s still a terrible precedent to set. Preliminary injunctions can still be granted by district courts, but now they need to be brought in the form of a class action and all the tediousness that entails. ACLU thankfully had one ready to go it seems just in case of this and it’s been filed already.

Nevertheless, this also enables insane infringement of the first amendment. There is nothing stopping him from declaring membership of a particular political party is illegal, including state parties, and then requiring each state to independently challenge under a restricted class action. It’s ludicrous.