Timecop

Let us assume, for argument's sake, that had Hitler not committed suicide during World War II, he would have been successfully prosecuted and sentenced to death or life imprisonment, and that we find such an outcome acceptable. Then, let us assume that we have access to to time travel technology that would allow us to go back in time and exact the same sentence on Hitler before his rise to power; in other words, go back in time and assassinate or kidnap him. Would this be an acceptable course of action?

For bonus points, compare the situation of having time travel technology at the point in time that the Nüremberg trials were conducted, with the situation where time travel is only developed many years later.