@aral It's a badly posed question anyway, because there are non-lethal options to do with baby Hitler.

You could mildly maim Hitler so he would be exempt from WW1 service for example. Or you could abduct Hitler and relocate him elsewhen to be raised as just another abandoned baby.

There may be unexpected consequences though. Hitler did not invent fascism: Without him, it's possible the war may happen, but Germany could be lead by someone with more military competence.