The Church has taught that the death penalty issue is a prudential judgement rather than a non-negotiable the way abortion is.  

Trump has major issues when it comes to the sanctity of marriage, it is one of the reasons I cannot support him despite my generally conservative politics, but Hillary viciously attacked the women who accused Bill Clinton of infidelity.  Just take a look at how she treated Monica Lewinsky.  She referred to her as a "narcissistic loony toon".  She is no pillar of the sanctity of holy matrimony, even if Trump happens to be more of in your face about it right now.