Sanctions are like a vaccine which when overly or misapplied lose their effectiveness

Sanctions are like a vaccine which when overly or misapplied lose their effectiveness. Trump's unilateral decision to discard the Iran Nuclear deal and reimpose the sanctions regime that Europe, Russia and China had agreed to bring Iran to the table to make the deal in the first place and with the full expectation they would be imposed again only with their agreement.  Now we have Russia in disagreement with sanctions altogether and Europe and China partially so. Europe’s disagreement will test U.S. based financial sanctions because they have the wherewithal and currency to counter them given a little time to tinker and develop workarounds just like a good microbe would. China can ignore the sanctions and buy oil at a discount from those rejecting it by blindly following U.S. demands to cease business dealings in Iran. And most dangerously for American power all three spheres of influence are aligned against the U.S.