> the test for whether a donation is a bribe.

Donations are always bribes.

> Donations to a politician are to the person.

Isn't that how bribery is normally done?

> It’s not a proxy for buying an outcome.

Perhaps not precisely, but it is a proxy for attempting to influence an outcome.

> under the law, a politician can’t rip you off by taking your money and then voting contrary to your desires.

Isn't that in conflict with:

> it is illegal to tie a donation to a particular position, vote, or action by the politician.

Are you saying that if I give a politician money and express my desire that they are then legally bound to vote according to my desire? Sounds like buying votes; I'm pretty sure that's not condoned by the law.