Nate Silver took a stab at it but even he doesn’t sound terribly confident in his numbers. People are starving for a poll showing the effect of a Castle write-in bid on the race, though, so until we see some sort of proper survey next week, this’ll have to do.

The bad news for Republicans, obviously: Castle wouldn’t necessarily tip the race towards her, as I and others thought it might. The good news: It dramatically improves her chances, cutting Coons’s 16-point lead over her in the last CNN poll neatly in half. And of course the model doesn’t take into account the strategic considerations that Delaware voters will face if the race is this tight on November 2. My sense of strategic voting is that it benefits the candidate people see as the lesser of two evils; given the media push to paint O’Donnell as a crank because of the “witchcraft” nonsense etc, the lesser evil here to most voters is probably the cipher Coons, which means some moderates who are in Castle’s column right now might break for the Democrat once they’re in the booth simply in the interests of ensuring O’Donnell’s defeat. Then again, maybe Castle’s name recognition is sufficiently high in Delaware that moderates and indies will stick with him to the bitter end, thinking he can pull the upset and making it a true cliffhanger on election night.

Two interesting points from Silver:

Mr. Castle could receive a decent number of Democratic votes. Polling that pitted him head-to-head in a (now hypothetical) one-on-one matchup against the Democratic nominee, Chris Coons, had shown him getting about one-third of the Democratic vote. On the other hand, Mr. Coons has perhaps become a little bit more entrenched than the Democrat in Alaska, Scott McAdams, simply because — in contast to Mr. McAdams — Mr. Coons had become the overwhelming favorite to win his race the moment that Ms. O’Donnell became the nominee. There may be an element of loss aversion among Democratic supporters of Mr. Coons, who could be less likely to support Mr. Castle in practice than they might have been in theory…

One dynamic that may be more favorable to Mr. Castle is that it seems conceivable he could win with as little as 35 percent of the vote. It seems probable to me that Ms. O’Donnell’s support is going to hover in the area of 30 percent — not a lot higher, not a lot lower — which was about the percentage of voters who had a favorable impression of her in the Public Policy Polling survey. That would leave Mr. Castle and Mr. Coons to fight over the remaining 70 percent of the electorate, making half that total — 35 percent — the magic number.

Yeah, unlike Alaska, which has always been expected to stay red, the Dems now have a legit chance of flipping a seat that was headed towards the GOP back into their column. Democrats who like Castle might be extra reluctant to part with that by defecting to the RINO. The possibility of a 35/34/31 race is pure gold for O’Donnell supporters specifically and Republicans generally, though, since the margin is so thin that a massive GOTV push at the very end could lead to her pulling the upset. Specifically, if she can peel off an extra 10 percent of independents from both Coons and Castle — and she’s got $2.5 million in the bank right now with which to do it — the race would be an almost even three-way split. The macro-point, though, is that the specific numbers don’t matter all that much right now. However they shake out, Castle’s entry into the race would push roughly 65 percent of the votes in Delaware into the Republican column — not enough to guarantee victory for either him or O’Donnell, ironically, but better than the 50-55 percent that are currently predicted to go Democratic. If you prefer either O’Donnell or Castle to Coons, if only for the sake of maximizing the odds of a Republican majority in the Senate, then you probably want Castle in to bring that about. If you’re in the “true conservative or bust” camp, then obviously you don’t. I think that’ll be the only real takeaway from whatever the polls show next week.

For your viewing pleasure, here’s Coulter jabbing at sore-loser RINOs a few nights ago on Hannity’s show while helping to lower expectations about taking back the Senate. As you’ve probably already seen elsewhere, Bill Maher’s latest archived clip of O’Donnell shows her arguing in the 1990s that evolution is a myth. That might hurt a tiny bit more in a blue state like Delaware, but have a look at this Gallup poll taken last year on the anniversary of Darwin’s birthday. How much is it going to hurt really?