The battle for the US Senate, updated

It's been almost six weeks since my last update, and I am not as enthusiastic about the Democrats maintaining control of the upper chamber as I was then.  Nate Silver has something to do with that.

The FiveThirtyEight Senate model is launching (September 3). We’ll be rolling it out in stages, with additional features, functionality and further methodological detail. We’ll also be unveiling our new set of pollster ratings and publicly releasing our database of all the polls used to calculate them. So there’s a lot more to come.

But if you’re looking for a headline, we have two. First, Republicans are favored to take the Senate, at least in our view; the FiveThirtyEight forecast model gives them a 64 percent chance of doing so.

The reasons for the GOP advantage are pretty straightforward. Midterm elections are usually poor for the president’s party, and the Senate contests this year are in states where, on average, President Obama won just 46 percent of the vote in 2012.¹

Democrats are battling a hangover effect in these states, most of which were last contested in 2008, a high-water mark for the party. On the basis of polling and the other indicators our model evaluates, Republicans are more likely than not to win the six seats they need to take over the Senate. This isn’t news, exactly; the same conditions held way back in March.

An equally important theme is the high degree of uncertainty around that outcome. A large number of states remain competitive, and Democrats could easily retain the Senate. It’s also possible that the landscape could shift further in Republicans’ direction. Our model regards a true Republican wave as possible: It gives the party almost a 25 percent chance of finishing with 54 or more Senate seats once all the votes are counted.²

There is much more and deeper analysis at the link.  The other factor clouding my optimism is the Brothers Koch and their massive piles of campaign money coming to the Republicans' rescue.

The secretive political network of conservative billionaires Charles and David Koch has aired more than 43,900 television ads this election cycle in an attempt to help Republicans take control of the Senate in the upcoming November election.

That amounts to nearly one out of every 10 TV ads in the 2014 battle for the Senate according to a new Center for Public Integrity analysis of data provided by Kantar Media/CMAG, an advertising tracking service, covering spending from Jan. 1, 2013, through Aug. 31, 2014.

The total includes the six most active nonprofit groups in the Koch brothers’ coalition: Americans for Prosperity, the American Energy Alliance, Concerned Veterans for America, the Freedom Partners Chamber of Commerce, Generation Opportunity and the 60 Plus Association.

Their prominence has led to denunciations by Democrats, and praise from Republicans, as they’ve bombarded incumbent lawmakers with negative ads and exulted conservative challengers. No other right-leaning coalition has been as active.

Didi I mention that Harry Reid has called a Senate vote for Monday, September 8 on revoking Citizens United?  Now's the time to call your Senator, especially if their names are John Cornyn and Ted Cruz.  That's after you sign the petition and send them a personal e-mail (find them at the link in this paragraph).

Koch-connected groups reportedly intend to spend $290 million to help Republicans make gains in Congress this November. Thus far, Kantar Media/CMAG spending estimates indicate the groups have invested at least $14.5 million. This amount is undeniably a conservative estimate, as it includes only TV ad buys — not production costs or expenditures related to radio ads, online ads, direct mail, canvassers or other activities.

These so-called “dark money” nonprofit groups are not required to disclose their funders to federal election regulators, unlike candidates, parties, political action committees and super PACs.

And although election-related advocacy can’t be the “primary purpose” of these groups, they’ve nonetheless established themselves among the nation’s most powerful political forces.

The dark money is gushing into our democratic republic like a pipeline leak into our water supply, fouling everything it touches.

Through the end of August, this spending spree has included about 8,600 ads in North Carolina, 6,900 ads in Louisiana, 5,800 ads in Iowa, 4,900 ads in Michigan, 4,700 ads in Arkansas, 4,600 ads in Colorado, 3,600 ads in Alaska and 2,400 ads in Oregon, according to a Center for Public Integrity review of Kantar Media/CMAG data.

And it's only a drop in the bucket of what's to come.  We'll be immune to much of it in Texas, since Cornyn's challenger, David Alameel -- deep-pocketed, but too weak progressively speaking -- has yet to make a difference in his race.  But dark money in Texas is definitely a concern.  You may recall that Rick Perry vetoed a disclosure bill that came out of the last legislative session.

Let's review again the Senate races that will tip the scales.

In three states currently held by Democrats - Montana, South Dakota and West Virginia - Republican victories are all but certain, leaving the GOP only three pickups to wrestle control from the Democrats.

In North Carolina, New Hampshire, Arkansas, Colorado, Alaska and Louisiana, Republican challengers threaten to knock off Democratic incumbents. Three more races - Iowa, Georgia and Michigan - feature open races where the Republican candidate stands a good chance, offering nine possibilities in total.

It's not all about the Republicans on the offensive, however. While far fewer than the Democrats, Republicans still have a few seats they'll have to vigorously defend: Kentucky, Georgia and, to a lesser extent, Kansas.

To a greater extent, Kansas.  And that's despite the KSSOS ruling yesterday that the Democrat who quit earlier in the week must remain on the ballot.  The Republicans are officially panicked that one of their locks is now a tossup.

I also think Mitch McConnell is toast, and Michelle Nunn is all but a prohibitive favorite today.  Mark Begich, despite this recent misstep, has run an extraordinarily good race -- he's effectively distanced himself from Obama in deep red Alaska -- and New Hampshire is smart enough not to elect that carpetbagger Scott Brown.  I don't think Michigan is flipping, either; they have a deeply unpopular Republican governor and a lousy economy, and that state is still blue.

Iowa is a real horse race and will be all the way to the end, and the other states I will watch to see if the GOP can get the three they need are North Carolina (Kay Hagen, D inc.), Arkansas (David Pryor, D inc.), Colorado (Mark Udall, D inc.), and Louisiana (Mary Landrieu, D inc.).

Hagen and Landrieu aren't running away from Obama; they need boosted African American turnout in their states to get past the finish line.  Pryor seems to be both savvy and lucky.  Udall's contest is see-sawing back and forth between he and his challenger, the odious Cory Gardner, and it has many moving parts, among them women's issues and immigration.  Of the four Democratic incumbents, Udall's race is the closest IMHO.  If Mitch McConnell rights the ship, Kansas and Georgia hold, Iowa falls, and one of CO, LA, NC and AR go red, the GOP gains the narrowest of majorities.

Still a tall order but within their grasp.

But if McConnell loses, Nunn wins, and Iowa stays blue then the Republicans have to win all four.  I don't see that happening, but it depends, across the board and across the country, on weak Democratic turnout defying somewhat historical odds and turning back the red wave.  We'll only know more about that as Election Day draws close.

Update: A few third party candidates might have a say in the matter.