There are some key storylines we're keeping an eye on for the House campaign as we head into summer. There are enough House seats competitive, or potentially competitive, this year that control could certainly be at issue come the fall. But that's more than just a number - we should also pay attention to key groups and regions that will help decide matters.
Looking at the more competitive and potentially competitive districts today, they're fairly spread around. There are a dozen competitive each in the West and South, 15 in the Midwest. There are fewer in the Northeast (where Democrats have been dominant on many levels of late) but the number that are potentially competitive there is in double digits.
The Midwest and West, considered broadly, look like the swing regions. In 2006, the last midterm, Democrats did well in the Midwest (winning 52 percent) and West (54 percent) that keyed their gains, and reversed Republican percents in those areas from the preceding midterm in 2002 by five points each.
One thing to watch, over the course of this year, is if the GOP can once again flip back those regional edges.
Back when they lost the House in 1994, the Democrats conceded seats around the country but of particular note was their losing more than 20 seats in the South and border states. In fact, they entered that election holding a majority of the seats there. Part of that election's storyline sixteen years ago was as a final chapter in the course of a wholesale changeover to the region's GOP-leanings today.
Suburbs and Rural Areas
Suburbs are traditionally a much-discussed "swing" area and suburban districts could again hold the key to House control.
Looking by type of region, in 2006 Democrats had the edge in the suburbs overall, 50 percent to 48 percent and held their own in small cities and rural areas, losing by just two points, which doubtless contributed to their making gains across many types of districts.
In 2008 again, Democrats had an edge in the suburbs and held even in small city and rural regions. Not all districts fall neatly and entirely into categories of urbanity, but those patterns do have a lot to do with the Democrats' recent success across districts with varying layouts, including some more rural ones. If the GOP can turn that around this year that'll be a big factor in winning back the House.
The Democrats posted percent gains 2008 over 2006 in over 80 suburb-heavy districts, which helped them pick up some of those seats last cycle, and now - not coincidentally - many of them are competitive again.
These include, for example, close-watched contests like the Ohio 1st and 16th (where Dems gained 5 and 14 percent respectively) the Pennsylvania 3rd, the Nevada 3rd, and the Florida 8th, also seats that look to be hotly contested again this year.
There are also a few districts with sizeable rural areas in which the Democrats showed gains from 2006 to 2008 which could be competitive this year (and thus dependent on those gains) including AZ-1, NH-2, to a lesser extent, places like NC-11 and PA-10.
The Recent Gains and Freshman
The Democrats are playing defense right now. Part of that is simple numbers: the inroads Democrats made in usually-Republican districts over the last two cycles, helped by a tough economy and voter dissatisfaction with the war - seats that would now be hard to hold over multiple cycles.
There were 49 seats in which Democrats were elected to the House while John McCain carried the district, and the great majority of them are - almost by definition - competitive this year. This is especially true of the dozen freshman members among them.
While incumbents generally do well in House elections, freshman members are historically among the most vulnerable incumbents, in part because they haven't had as much time to build up as much name recognition, constituent service or funding for the district as longer-term members, and as such can be more easily buffeted by the winds of partisan voting patterns.
In 2010 Democratic freshman are spread around the country, so that things don't hinge as much on one region. Examples, in no particular order, of places to watch for possible indicators of the fates of freshman range from the Arizona 1st (Ann Kirkpatrick) and New Mexico 2nd (Harry Teague) and the Colorado 4th (Betsy Markey) out west, to the Ohio 16th (John Boccieri) and Pennsylvania 3rd (Kathy Dahlkemper) back east and down to Florida's 24th (Suzanne Kosmas).
Anthony Salvanto is CBS News Elections Director. You can read more of his posts in Hotsheet here.