“Why I Hate Barack Obama,”
There may be other nuances here, but I’m in the “love the sinnder, hate the sin” camp.
Article 8. Whether we ought to pray for our enemies
Objection 1. It would seem that we ought not to pray for our enemies. According to Romans 15:4, "what things soever were written, were written for our learning." Now Holy Writ contains many imprecations against enemies; thus it is written (Psalm 6:11): "Let all my enemies be ashamed and be . . . troubled, let them be ashamed and be troubled very speedily [Vulgate: 'Let them be turned back and be ashamed.']." Therefore we too should pray against rather than for our enemies.
Reply to Objection 1. The imprecations contained in Holy Writ may be understood in four ways. First, according to the custom of the prophets "to foretell the future under the veil of an imprecation," as Augustine states [De Serm. Dom. in Monte i, 21. Secondly, in the sense that certain temporal evils are sometimes inflicted by God on the wicked for their correction. Thirdly, because they are understood to be pronounced, not against the men themselves, but against the kingdom of sin, with the purpose, to wit, of destroying sin by the correction of men. Fourthly, by way of conformity of our will to the Divine justice with regard to the damnation of those who are obstinate in sin.
Objection 2. Further, to be revenged on one's enemies is harmful to them. But holy men seek vengeance of their enemies according to Apocalypse 6:10, "How long . . . dost Thou not . . . revenge our blood on them that dwell on earth?" Wherefore they rejoice in being revenged on their enemies, according to Psalm 57:11, "The just shall rejoice when he shall see the revenge." Therefore we should not pray for our enemies, but against them.
"Reply to Objection 2. As Augustine states in the same book (De Serm. Dom. in Monte i, 22), "the martyrs' vengeance is the overthrow of the kingdom of sin, because they suffered so much while it reigned": or as he says again (QQ. Vet. et Nov. Test. lxviii), "their prayer for vengeance is expressed not in words but in their minds, even as the blood of Abel cried from the earth." They rejoice in vengeance not for its own sake, but for the sake of Divine justice.
Objection 3. Further, man's deed should not be contrary to his prayer. Now sometimes men lawfully attack their enemies, else all wars would be unlawful, which is opposed to what we have said above (Question 40, Article 1). Therefore we should not pray for our enemies.
Reply to Objection 3. It is lawful to attack one's enemies, that they may be restrained from sin: and this is for their own good and for the good of others. Consequently it is even lawful in praying to ask that temporal evils be inflicted on our enemies in order that they may mend their ways. Thus prayer and deed will not be contrary to one another.