It is possible to have two competing and contradictory moral obligations, that does not mean that either moral obligation ceases to exist. I think "save lives if possible" out weighs "follow the law", but that doesn't mean that the moral obligation to abide by the law goes away. I do think it is often moral to break the law, but it has to be in service to a greater morality.

Your are equating the morality of opposing the Holocaust with the morality of opposing sanctions in that you assert that they both out weigh the moral obligation to follow the law.