The Citizens United ruling states that "spending is speech". Ignore the "corporations are people" bit for now. Point is, that spending money is a form of speech, according to the US supreme court.
Also, slightly more dubiously, but still with fairly strong precedent, anonymous speech is protected under the free speech amendment. Its pretty much a given that one can make anonymous speech whenever, one can't be denied the right to speak because he or she did not present an ID, for example. However, there
have been cases in which anonymous speakers have been compelled to release their identity after the fact if their speech was false and supposedly caused monetary damage to a third party.
Given this logic, doesn't it seem incredibly hard to legally justify AML laws, which in cases can specifically state:
"Required the verification of identity of purchasers..." (Anti-Drug Abuse Act of 1988)
Do you think there's any chance these laws could actually be eventually overturned if brought to the supreme court?