I don't know. You can waste a lot of effort on convincing people of the need for security, establishing significant security, not weirding people out in the process, and actually sticking to it, only to find out that it's not as good as you think/it's yet another program with some sketchy back door built in. Or you do everything right and there's a fed in your group in person, a tactic they've used for at least a century. Or there isn't, but a serious adversary can piece together who's in the group and when you're meeting based on public posts and phone data.

This isn't saying orgs should take zero steps on information security, more that you're never going to be able to hide a domestic political group from the U.S. government. Expect leaks and wreckers from the start and you can set up ways to minimize their harm.