Is there a U.S. based Chaos Computer Club (CCC) or CCC like group?
One notable difference is a much closer connection to e.g. intelligence services.
On the other hand, the relationship to democratic processes, as well as the stance on state/federal involvement in IT problem spaces, seems to differ between Germany and the US.
Again: I'm an outsider and would actually like to hear from others how they see this.
Some CCC hackers had a pretty good relationship with the Russian KGB. They got information about a wide range of US military secrets including details about the Space Defense Initiative (SDI). They were so successful that they wound up dead and a movie was made about them. Since then the CCC has to be heavily infiltrated by all kinds of Intelligence Services.
I think this more served as a cautionary tale to not get involved with this kind of agencies at all.
However since then the CCC has been very honourable and I have nothing but respect for them.
Infiltrating the CCC would be akin to infiltrating Antifa. Sure, you can get close to a group and learn their secrets, but you can't get close to the center of it because it has none.
As mentioned by others, the EFF's Electronic Frontier Alliance tries to act as a regional group for these types of things, but in my experience it's pretty dead (at least the Utah group has been completely unresponsive).