Can Catholics support the lesser of two evils? Short answer, no. In fact it's so hilariously no that it was hard for me to write this article without opening on a joke.
In the American lexicon voting for the "lesser of two evils" has become commonplace. That being said there is an inherent error with how we use it. When Americans use the phrase we most often mean "vote for someone you disagree with but, ultimately, desires the good of the nation". Because how often are we given the choice between two truly evil candidates.
Hello 2016.
Yes there is no doubt in my mind that Hillary Clinton is incompetent at best, corrupt at worst, and overall a candidate that represents the worst of the political dynastic class. There is also no doubt in my mind that Trump is a possibly insane narcisist who lies constantly, flirts with authoritaranism, and allows bigotry to return to the mainstream in a disgusting and un-American fashion.
So what are Catholics to do?
In the world of Moral Theology there is something called "The Double Principle Affect" which Thomas Aquinas thought up in the Summa Theologica. This addresses the nature between good actions and bad actions with the essence being one must always choose good and evil is only permitted as an unintended consequence. For example, killing someone in self defense. You are trying to preserve your life and the fact that the man dies is an evil consequence. If a man attacks you and you intend to murder him, then that is you selecting evil.
Therefore, back to the 2016 election. There is no moral justification for choosing either candidate because you will be directly choosing evil. Even if you believe Trump is less bad then Hillary or Hillary is less bad then Trump you're, at best, Utilitarian which is the same camp that believes abortion is good because it lowers crime rates and killing civilians is okay because they might have been terrorists.
Specifically there are issues with these two candidates specifically. The Hillary Clinton side is pretty straightforward. Catholics are not allowed to vote for pro-choice politicians and pro-choice politicians are not allowed to receive communion. Pretty open and shut. Granted, on the Trump side, the Catholic church has never openly condemned authoritarian populism but I'm going out on a limb and say that calling the Holy Father a puppet of the Mexican government, accusing him (the freaking Pope) of not seeing the poverty of central america, (somehow) questioning the Pope's ability to judge other's faith, and vaguely threatening the Vatican with an ISIS attack probably does not garner much support.
Now I'm not telling anyone not to vote. Everyone should vote down ballot for politicians who are sane, capable, and hold America's interests at heart. The Catholic vote is a powerful one in American politics and it has been this continued compromise on American values that led to the Republicans nominating Trump and the Democrats nominating Clinton. We've hit rock bottom, take a stand, rise above. This election has taken so much from us, stick to your morals, it's all we have left.