"A counterproductive Washington policy in recent years has been to boycott and punish political factions or governments that refuse to accept United States mandates. This policy makes difficult the possibility that such leaders might moderate their policies."
So writes former US pres. Jimmy Carter in an op-ed piece "Pariah Diplomacy" in the NY Times.
As Carter writes there are "two notable examples" of what he saying. Read them, in full, here.