Yes, yes, this comic has a political theme, which I generally avoid, but it’s a good example of the subjunctive mood. In English, many verbs show that they are in the subjunctive only by having the appropriate auxiliary verb attached. I don’t recall ever hearing of the “pre-existing conditional tense,” however. Maybe pre-existing conditional clause, though.
In Greek, for those of you who are curious, “I give” is didomi (short o, omicron) and the equivalent of “I would give” is didoomi with a long o (an omega). They also have an even stronger mood, called the optative, meaning “I wish I could give.” That’s didoimi. Now you know Greek!