Actually, there is such a thing as the lesser of two evils. For instance, the choice of going to war, when done rightly, always involves the judgement that the evils inherent in war are less than the evils of permitting the circumstance that occasioned the war to go on unchecked. We Orthodox have a canonical penance to be applied to those who kill in war, and I’m sure it’s applied to those who kill in self-defense, but it is far lighter than the canonical penance for murder. Homicide is always evil: justifiable homicides are those cases in which the evil of homicide is the lesser of two evils. Stealing food is evil, but it may be the lesser of two evils if otherwise one’s children will starve, and so forth.
Likewise to political candidates, there are greater evils (for instance doctrinaire post-colonialist multiculturalist Red-diaper babies whose instincts lead to genuinely harmful decisions on essentially every issue) and lesser evils (for instance squishy convictionless centrists who stake out leftish positions on some issues to be thought progressive, but occasionally get things right).
Do you also believe there are degrees of sin? I don’t all sin is abhorrent to God - He does not ‘grade on a curve’.