Oh I believe they can. Isn't it called a supoena?

Yes. I mean, that's the whole point of that part of the fifth amendment. There would be no need for an explicit carveout of self-incrimination if the government didn't have the general ability to compel witnesses to testify.

Exactly. I suppose in some sense you have to admire America’s ability to produce people who believe the government has ~zero authority.

“The government can’t possibly do [basic function of every government since dawn of tribal life], can it?”

Yes indeed it can.

There’s just so much freedom over here it’s hard to tell where ends and where it begins.

They can compell you testify if they offer you immunity.

The standard other exemptions are doctor-patient, attorney-client, religious leader-religious person, and spousal confidentiality laws. Some, but not all, states also shield journalist's sources. In the last case, in states without a shield law, going to jail to protect a source's identity is considered a professional honor.