As Glenn Greenwald (again) properly asks (to paraphrase), "What are Democrats prepared to do about the November 5th sentencing of Saddam Hussein?" How convenient, eh?
In truth, there's probably little they can do about it except keep pointing it out to the GOP sheep.
Every halfway decent trial lawyer knows that if your adversary has some bombshell document or witness which packs such emotional punch that it can overwhelm all other facts, you don't just sit around and passively wait for them to unleash it. You do the opposite.
Before they can use it, you take the document or witness and talk about it as much as possible, as aggressively as possible, and as early as possible, so that (a) the jury knows it's coming and so you deny your opponent the dramatic shock value of it, (b) it is clear that you are not afraid of its impact, and (c) the jury hears about it from you first, rather than your adversary, so that you're the one who defines it and, from the beginning, they view it from your perspective, not the other side's. In sum, by preemptively seizing on and using the other side's planned dramatic bombshell, it makes it a completely expected non-event when it finally happens.
More subtly -- but perhaps even more importantly -- by seizing upon their greatest strength, it conveys that you actually think the other side's great "secret weapon" actually helps your case, because it demonstrates how weak they are. If something as ineffective as this is what they think is their big, magical weapon that will save them, that is a pretty compelling reflection of their desperation, of their desire to distract from their real issues, and of the lameness of their position on the merits.