Senate Ratings Changes: Races Shift as Playing Field Takes Shape

September 3, 2012 · 12:22 AM EDT

In the wake of GOP nominee Todd Akin’s media meltdown, it’s not just Missouri that appears to be trending away from Republicans lately.

After moving the Show-Me State to Pure Toss-Up last week, we are moving it again, to Lean Democrat. Akin, who held a double-digit lead before he made his infamous comments about rape and pregnancy, continues to resist pleas from GOP colleagues that he exit the contest.

Although Akin is now on the attack with a new TV spot, “Six Seconds -- Six Years,” in which he compares his “six second mistake” with incumbent Senator Claire McCaskill’s six years in office, it is far from clear that he will be successful in reshaping the race, or in raising the money he needs to compete. Plus, normally sympathetic outside groups are not inclined to help.

McCaskill isn’t pummeling Akin now, preferring to run positive ads about herself and keep her fingers crossed that the congressman remains on the ballot past the last September deadline. At that point, you can be sure she will unload on him, citing not only his comment about rape but also comments about the school lunch program and repealing the 17th Amendment to the Constitution.

Given where the race stands, McCaskill deserves to be regarded as the favorite in the contest. If Akin does leave the ballot before the late September deadline and is replaced with any number of potential fill-ins, McCaskill would likely return to underdog status.

We are also moving two other Senate races in Democrats’ favor and one toward the GOP: New Mexico from Toss-up/Tilt Democrat to Lean Democrat, North Dakota from Toss Up/Tilt Republican to Pure Toss Up and Wisconsin from Pure Toss-Up to Toss-Up/Tilt Republican.

Much like the Hawaii Senate contest, Republicans have a quality nominee in New Mexico but face a challenging political landscape. Former Rep. Heather Wilson (R) has a reputation as a moderate, but the race appears to be slipping away, according to multiple surveys. What once looked like an even match-up with Rep. Martin Heinrich (D) now looks like a significant lead for the Democrat, in a state that President Obama will likely carry in November. National Republicans appear to think so as well, as the NRSC pulled their ad reservations for the fall last week.

Our initial view about the North Dakota Senate race was that the Republican lean of the state would allow Rep. Rick Berg (R) to overtake and then open up a lead against former Attorney General Heidi Heitkamp (D). That hasn’t yet happened. Heitkamp is running a solid campaign and remains popular, while Berg hasn’t been able to put any distance between himself and his opponent. It is still very possible that Romney’s strength in the state will benefit Berg, helping him carry the state in the fall -- and it was likely no accident he was one of the few Senate candidates in a tough race to take the stage in Tampa. But this race has been close for months, and it is still unclear whether Berg or Heitkamp will emerge victorious in November.

In Wisconsin, multiple surveys show that former Gov. Tommy Thompson leads Democratic Rep. Tammy Baldwin in the general election. Thompson, a longtime fixture in Badger State politics, certainly has crossover appeal in this severely polarized state, but his primary contest also bled his coffers dry. Baldwin still has a significant cash lead. Smart Democrats argue, quite reasonably, that some Democratic voters don’t know the congresswoman and that they only need to convince Democrats to vote for Baldwin to turn the race around. That’s certainly true, but the burden is still on Baldwin’s campaign. And while she is trying to bring Democrats home, Republicans will be trying to hold them and woo undecided voters. This race remains very competitive, but, at least for now, Thompson has a slight edge.

Finally, we are not now moving the Indiana Senate race, because we continue to believe that Romney’s likely big win there (along with Republican gubernatorial nominee Mike Pence’s likely victory) will benefit state Treasurer Richard Mourdock, who defeated Sen. Richard Lugar in the GOP primary. But polling continues to show Murdoch locked in a tight race with Rep. Joe Donnelly (D) in the general election, and Murdoch may well be just one big mistake away from finding himself in a much more difficult race than we expected. Still Lean Republican, but keep an eye on this one.