While the shift from 5 percent odds to 54 percent odds is a huge jump anyway, it would be much higher if Orman were to simply confirm he would caucus with the Democrats. On the surface, it's a reasonable assumption that he'd caucus with the Democrats. Orman ran for the Senate in the Democratic primary in 2008, and his issues page — where he says, in rather oblique fashion, that he's pro-choice and supports immigration reform — makes it clear he'd be very uncomfortable as a Republican.
However, Orman isn't saying that. (Nor would it be wise for him to do so; he'd probably shed a number of moderate Republican votes as soon as he put on a blue shirt, in a state where he can't afford to lose any of those votes.) Instead, he tiptoes around the issue, saying that he'd seek to work with "work with the other independent Senators to caucus with the party that is most willing to face our country’s difficult problems head on and advance our problem-solving, non-partisan agenda." But more importantly, he also says:
With that said, if one party is clearly in the majority, he will seek to caucus with the party that was in the majority as that would be in the best interest for the state of Kansas.
Here's where the modeling gets tricky, and it starts to cross over from mere poll aggregation into game theory. In order for the Democrats to "win" the Kansas race, they have to not only see Orman defeat Roberts, but they also have to garner a majority of the other seats anyway. If Orman wins, but the Republicans already have a majority with or without Orman, then Orman just caucuses with the Republicans anyway, and the Democrats have "lost" that race too. In other words, here are the potential scenarios:
Democrats win 48 seats, Republicans win 51 seats: Orman caucuses with the Republicans, pushing that total to 48 D, 52 R.
Democrats win 50 seats, Republicans wins 49 seats: The Democrats will have a majority anyway because of Joe Biden's tiebreaking vote, so Orman caucuses with the Democrats, pushing that total to 51 D, 49 R.
Democrats win 51 seats, Republicans win 48 seats: Orman caucuses with the Democrats, pushing that total to 52 D, 48 R.
Democrats win 49 seats, Republicans win 50 seats: Here's where the real uncertainty enters the picture. There's no "clear" majority (in other words, if Orman throws in with the Democrats, the Dems will have a majority because of Biden; if he throws in with the Republicans; the Republicans will have a majority), and Orman needs to go one way or the other, unless fellow indie Angus King decides to leave the Dem caucus and join Orman on a two-person magical unicorn ride. Our model, awesome as it is, still can't predict Orman's state of mind, so in all 49 D/50 R scenarios, we're allowing Orman a 50 percent chance of caucusing with the Dems and 50 percent chance of caucusing with the GOP.
So that's why Democratic odds of "winning" the race are 54 percent, even though Orman's personal odds of winning the race are much higher. In all scenarios where the GOP ends up with 51 seats or more regardless of what happens in Kansas, and half of the ones where they end up with 50, an Orman win just pads the Republican total further.
And that's why our histogram no longer resembles a neat, tidy bell curve any more (if you want to see what it looked like, check our post from last week). Scenarios where the Democrats win exactly 50 seats, which used to be the modal result, are now pretty rare, now mostly involving permutations where Roberts wins the race instead. Most of those 50-seat scenarios instead get turned into 51-seat scenarios, since at that point Orman gets turned into a bonus Dem. Fifty-one seats is the new mode, while fifty seats is the new median. Either 50 or 51 is enough for control, so now the Democrats retain control in the majority of all Monte Carlo simulations.
While Kansas is largely responsible for the Dems' move upward, if you look at the totem pole, you'll also notice that Mary Landrieu's odds in Louisiana have increased significantly (perhaps too much to be truly realistic, from 47 percent to 76 percent). That's thanks to one poll that didn't attract much attention, a poll released by the Senate Conservatives Fund that had Landrieu leading her likely runoff opponent, Republican Bill Cassidy, 49-43. Why, you might be asking, would a right-wing group leak a poll showing a Republican in such dire straits? Well, it was to show that their preferred candidate, Rob Maness, trailed Landrieu by slightly less (48-44), as well as improving his share in the jungle primary. Whatever their purposes, though, the model counts it as something of an own-goal, boosting Landrieu's averages even further because it's a Republican partisan poll and the model downweights Cassidy even further!
In addition, two polls that put Michelle Nunn in a small lead (after a long series of ones showing her losing) boosted her odds somewhat, from 14 percent last week up to 23 percent now. That's balanced, however, by several polls in Kentucky showing Mitch McConnell expanding his lead a bit, moving Alison Lundergan Grimes's odds there from 22 percent down to 18 percent.
Let me repeat these caveats until I'm blue in the face: As happy as this shift made me, the fact that the Democrats have a 56 percent chance of controlling the Senate this week is in no way
a prediction that they will
control the Senate, any more than, when we were talking about this last week, the fact that the Democrats had a 45 percent chance of controlling the Senate was a prediction that they will
lose the Senate. The overall proposition is still, entirely, a coin flip. The coin has simply gone from being very slightly weighted in one direction to very slightly weighted in the other direction.
Finally, let's take a look at the gubernatorial races. For one brief day, the median number of Dem-held state houses ticked up to 23, which would be a two-seat improvement over what they currently have. However, that ticked back down to 22 today, which is a one-seat gain. That's largely due to polling fluctuations in Florida, where a SurveyUSA poll on Tuesday gave Charlie Crist a 45-43 lead, but then a Univ. of Florida poll on Wednesday gave Rick Scott a 41-36 lead.
Overall Democratic odds of gaining gubernatorial seats continued to move up, though; it was at 52 percent last week, and now it's up to a 60 percent chance. That's in part due to improved odds in Georgia and Arkansas (which the Democratic candidates are still on track to lose, though), but more than anything due to Alaska, where there was an entirely separate switcheroo in a three-way race where the Dem and indie had been splitting the anti-incumbent vote.
There, Democratic nominee Byron Mallott dropped out to become the Lt. Governor on a ticket with independent candidate Bill Walker. What few polls we'd previously seen of a head-to-head matchup between Walker and GOP incumbent Sean Parnell showed a very close race, and even a Walker lead in one case, so that boosted Dem odds here from 1 percent to 37 percent. (To make things simpler, we're counting Walker as a de facto Democrat here, since policy-wise he'd be a big improvement on Parnell, even though there will be an "I" next to his name; there's no need to ask about who he's going to caucus with, seeing as how governors don't caucus with anybody, so Walker's individual odds are what's important.)
We'll be continuing to post updates like this several times a week, as we see if the Democrats can keep building on this momentum or not. Our permanent Poll Explorer Senate and gubernatorial pages are updated every day, so please check them frequently; you can bookmark them, or find them in the "Blogroll" list in the right column on the main Daily Kos Elections page.