Senate snapshot: Advantage Democrats

Barack Obama wasn't the only person who enjoyed a convention bounce. I've been doing this for the presidential race for several months. Now that we have a steady stream of Senate-seat polling, we can do it for the Upper Chamber as well.

The chart features the TPM polling composite for these races. The background color behind the state names indicates which party holds the seat. Bolded numbers indicate incumbent senators.

You might notice two key states missing'Maine, in which independent Angus King is winning easily, and should caucus with the Democrats, and Nebraska, where no one is polling because why waste money and time confirming Democrat Bob Kerrey is a bust?

Maine will be a pickup for Democrats, Nebraska will be a pickup for Republicans.

If we simplistically give each of these states to the candidate currently leading, Democrats would pick up Indiana and Massachusetts while Republicans would pick up Connecticut. Tally it all up, and Democrats would come out of the cycle, with this brutal Senate map, with a one seat gain. That would be nuts!

But it's not that simple. Undecided Senate voters tend to reflect the partisan makeup of their states. A few cycles ago Tom Coburn and his Democratic challenger Brad Carson were tied in pre-election Oklahoma polling, something like 42-42. Coburn ended up winning 53-42. I don't have a name for that phenomenon, but the same thing happened last cycle, when Rand Paul was roughly tied with Democrat Jack Conway in Kentucky late in the 2010 cycle, only to gobble up all the undecideds and win 56-44.

So we have several hard-partisan states in this list'Connecticut, Massachusetts, North Dakota and Indiana. Maybe Arizona. Indiana is debatable considering Pres. Barack Obama won it in 2008, but Democrats haven't been particularly competitive in the state since then.

If my theory holds, the Democratic advantage in Connecticut and Massachusetts should be enough to push our candidates over the 50 percent mark. Likewise, Republicans should be able to pull through in Indiana and probably North Dakota, though the latter is small enough that Democrat Heidi Heitkamp can potential break through with strong retail politicking.

Montana and Virginia are about as real a dogfight as you can get'both candidates in both states have been elected statewide, giving the races an incumbent versus incumbent feel. The Nevada numbers are encouraging'a heavy Obama GOTV operation in the state could make the difference, particularly with appointed Sen. Dean Heller underperforming as an incumbent. And finally, there's Arizona, where it'll all come down to whether Latinos turn out.

Finally, I've always said that Todd Akin's disaster would make the Missouri race competitive, rather than a guaranteed Democratic hold. The numbers seem to bear that out, and as disappointing as that might seem, fact is 27 percent of Missouri is evangelical. This is actually for the best'a blow out would increase pressure on Akin to drop out, which is why Democrats have laid off Akin until the magical Sept. 25 deadline. Once Akin can't be removed form the ballot, two things should happen'the Democrats will unleash the hounds, and Senate Republicans and Super PACs that have vowed to stay out will be under serious pressure to reconsider.

One thing's for sure'this is nowhere near the disaster map Democrats feared just six months ago. There's a realistic (if outside) possibility that we can actually emerge from this cycle picking up a seat or two. Worst case, we can still lose the Senate, though that looks to be a remote possibility for now.