Mojoey just did another rebuttal of the "Argument from Stalin." It occured to me that there's a much better rebuttal to be made:
1) Stalin was a mass murderer.
2) Stalin rejected Dawinian evolution. (Yup, that's right: he endorsed Lysenkoism)
3) Creationists reject Darwinian evolution.
4) Therefore, creationism will lead to mass murder.
This is of course tongue-in-cheeck, but rhetorically, it would probably work better than an abstract discussion of guilt-by-association.