Good point. It both cases the existence of a crime depends on how closely the two actions are related. If you literally gift something to someone with zero exp

Good point. It both cases the existence of a crime depends on how closely the two actions are related. If you literally gift something to someone with zero expectation of getting anything in return and later that other person happens to do something which benefits you. It's impossible to prove that is bribery. There has to be a strong connection the money and the action. There is a similar principle with blackmail. There has to be a strong connection between the money and the inaction. It's interesting to note that in both cases, a transfer of money usually causes harm to external third parties who are not aware of the transaction. It would be better for society if people did not accept bribes and if people did not yield to blackmail (e.g. if they just went to jail instead of continuing whatever they were doing which made them the target of blackmail in the first place).