It is not clear that Trump supports torture and killing non-combatants but for the sake of argument lets say he does. When both candidates support intrinsic evil we may vote for the candidate who would do the least harm. Again lets turn to the Magestrium:
*There is only one thing that could be considered proportionate enough to justify a Catholic voting for a candidate who is known to be pro-abortion, and that is the protection of innocent human life. That may seem to be contradictory, but it is not.
"Consider the case of a Catholic voter who must choose between three candidates: candidate (A, Kerry) who is completely for abortion-on-demand, candidate (B, Bush) who is in favor of very limited abortion, i.e., in favor of greatly restricting abortion and candidate (C, Peroutka), a candidate who is completely against abortion but who is universally recognized as being unelectable.
"The Catholic voter cannot vote for candidate (A, Kerry) because that would be formal cooperation in the sin of abortion if that candidate were to be elected and assist in passing legislation, which would remove restrictions on, abortion-on-demand.
“The Catholic can vote for candidate (C, Peroutka) but that will probably only help ensure the election of candidate (A, Kerry). Therefore the Catholic voter has a proportionate reason to vote for candidate (B, Bush) since his vote may help to ensure the defeat of candidate (A, Kerry) and may result in the saving of some innocent human lives if candidate (B, Bush) is elected and introduces legislation restricting abortion-on-demand. In such a case, the Catholic voter would have chosen the lesser of two evils, which is morally permissible under these circumstances.”
Bishop Rene Gracida*