[CPLX]

Unions primarily engage in collective bargaining with the employers of their members. The AMA is not a union.

[digbyloftus]

Very likely to be true and I wont disagree! I'm not actually even from the US so I'm unfamiliar with their scope. I disagree with the person I'm replying tos reasoning more than anything. Their objection was of a different nature than yours.

[MaysonL]

You're right, it isn't a union, it's a cartel!

[CPLX]

No, a cartel is a group of competing firms in the same industry that form an alliance.

The best analogy for the AMA would be something like a guild.