I think it's possible that, at least in the swing states, Obama's huge margins from earlier gave Democrats a boost downticket. At the debate, Romney succeeded in making himself a viable alternative which may have softened Obama's support, but I can't imagine the guy who's like "Hmm, this Romney guy might be alright, may as well vote for George Allen while I'm at it!" In fact, the prospect of a Democratic Senate tempering Romney's agenda might even solidify that.
It's weird. One idea was that it fired up the base who was now going to come out and vote. In that case, they weren't voting on Senate and thusly the Senate numbers should clearly improve (since it's base voting). But we're not seeing that so this kind of goes along with the belief that the base was going to begrudgingly vote Romney no matter what or if depressed, stay home (but they weren't at that point, yet)
The other possibility is that a bunch of swing voters (mostly undecided) went to Romney but stayed with the Democrat Senate (which is dumb, sigh). Of course, that means we wouldn't see a fading bounce. It could still happen if those voters are swinging back.
I guess the other thing that could be happening is what I call "soft" republicans. They're not the base, they may in fact be independents who always lean Rrepub in Presidential elections, but they don't care about anything but the President and until the debate had no interest in voting for him despite not liking Obama. But now they were interested. But they knew jack-all about anything else so when asked about the Senate they said "don't know" while the Dems picked up guys from elsewhere (soft Dems for example who got more interested after the convention). This poses a problem. These soft Repubs may eventually jump onto the Repub senate. On the other hand, these "soft repubs" may only be so in the case of President, but actually prefer Dem in Congress or are just voting based on name recognition in some cases.
But who knows, really.
That's good, would like to see movement in normal methodology polls too.
Gallup RV did move yesterday +1. We'll see this morning at 10AM if it goes to +5. That would put it at pre-debate status. If Gallup is tied in the LV model, that would be quite good. The two have generally been 5 points apart so far and I'm not buying their LV as the right number versus RV. I think they're underselling Dem turnout.