The Senate races are badly in need of an update, not only because it has been ages since the last ones but also because we finally know the full slate of nominees on both sides (excepting the GOP side of the Wisconsin race). The landscape looks much different today than it did back in April, and right off the bat I want to make a number of updates to reflect that:

The Wisconsin race has turned into a competitive one owing to the conservative lean of much of the non-urban portion of the state and the generally unfavorable environment for Democrats. The biggest thing working against the GOP in the Badger State is that both of their contenders are nobodies. The Feingold-Tommy Thompson matchup never materialized and we're left with two no-name businessmen to duke it out in the 9/14/10 primary. Most analysts have this as a toss-up but given the weak competition I have some confidence that Feingold will hold on.

Worse news for the Democrats: Blanche Lincoln (AR) appears to be toast and Evan Bayh's old seat (IN) is highly likely to change hands. Those are two good pickups for the GOP, and I will not be shocked to see the DNC, DSCC, and other funding sources cutting their losses on these two races soon. On the plus side for the Socialists, Dick Blumenthal appears to have the CT open seat well in hand, thanks in part to the tremendous crapulence of GOP nominee Linda McMahon, wife of WWF chairman/wrestler Vince McMahon. That should be a safe hold, and the Delaware race for Biden's open seat is less of a certain GOP pickup at this stage.

One race with the potential to get very interesting is in Alaska, where Lisa Murkowski has launched a write-in campaign in response to her narrow primary loss to Teabagger Joe Miller. Dividing the conservative vote could have disastrous results, opening the door for unknown Democrat Scott McAdams.

That is about the extent of the Democratic good news, however. The updated uncompetitive/safe races yield a three-seat pickup for the GOP:

The competitive races illustrate the problem with something I tried for the sake of simplicity this year: limiting races to two categories, either competitive or safe. In reality there are competitive races and there are races that are truly too close to call. Those are the four toss-ups you see here. The rest of the races are leaning pretty clearly one way or another (excepting Pennsylvania, which I'll explain in a moment).

Current polling shows Toomey with a decent lead over Sestak in PA, but I still have that one as a Democratic hold because of the exceptionally poor track record of Pennsylvania Republicans in the last few elections. Whether it's McCain choosing PA to make his 300-esque last stand or polls predicting Rick Santorum's re-election, statewide Republicans just don't seem to do as well as predicted lately. The state is just too urban for Republicans to have an easy go of it, although motivating 2008-like voter turnout is a pipe dream in the midterm.

With the GOP likely to pick up two from this bunch (the aforementioned AR and IN seats) that gives the GOP a five-seat gain with four toss-ups. If they win all four the Senate will be 50-50, generously counting anal warts like Lieberman and Ben Nelson as Democrats. The Democrats also must contend with the potential for those two corrupt little bastards to switch parties if the would-be GOP leadership offers them something useful.

From the Democratic perspective, the key over the next two months will be to throw everything at Pennsylvania, Colorado, Washington, and Missouri. Delaware is the most Republican-leaning of the coin flip races, and Mike Castle is a quality opponent. Washington is the safest bet, and Colorado can probably be held at tremendous cost. In Missouri, Roy Blunt's lead in the polls withers under the inviolable rule of Missouri politics: never bet against a Carnahan. That one will remain too close to call until the bitter end, most likely.

In future updates I'll focus more on the specifics of the four toss-ups plus Pennsylvania. For now, if everything goes right for the GOP the Senate will be 50-50. With anything less than a total collapse from the Democrats, the more likely outcome is 51 to 53 Republicans the morning after the election.