Report: Midterm Math Looks Similar to 2006

House Democrats, as we have been reporting now for months, have the wind firmly at their back this year. All signs are pointing to a better than 50-50 shot at taking control of the House, perhaps by a decent margin. Even so, we’ve also noted that Republicans have a built-in structural advantage — namely few swing seats to defend. Moreover, the conventional wisdom has held that the map has gotten much less favorable to Democrats in the House since 2006, thanks in large part to the fact that Republicans controlled the redistricting process in many significant battleground states in 2012, taking many formerly competitive seats off the table.

But, as Senate Leader Mitch McConnell warned everyone very early in the cycle, “don’t fall in love with the map.” In fact, when you look more closely at the kinds of districts Republicans are defending in 2018, they don’t look much different from those they had to defend in 2006. For example, there are about as many competitive GOP-held seats in play today in districts with a slight GOP lean (PVI of R+1 to R+5) (23) as there were right before the election in 2006 (22). And, while it’s true that there are few “low hanging fruit” type of districts for Democrats to pick-off (just 23 districts held by Republicans voted for Hillary Clinton), there weren’t many easy lay-ups in 2006, either. Back in 2006, Republicans held just 18 seats won by Democrat John Kerry in the previous presidential election. By the election of 2006, just 15 GOP-held seats (or 27 percent of the total number of GOP-held competitive districts), were in districts that had a slight Democratic lean (a PVI of Even to D+8). Today, of the 40 most competitive seats held by Republicans, 10 (or 25 percent), have a slight Democratic lean (Even to D+5).

In other words, it’s not that map has gotten that much worse for Democrats since 2006; the battleground itself has shifted. For example, in 2006, Indiana, Ohio and upstate New York accounted for 25 percent of the most competitive GOP held seats. This year, California, New Jersey and Texas account for 30 percent of the most competitive GOP seats. We’ve swapped upstate New York with Orange County, California and central Indiana for central New Jersey.

You will also notice that the plurality of seats won by Democrats in 2006 (40 percent) came not from Democratic-leaning seats, but from districts that had a slight GOP advantage. Another 23 percent of the seats Democrats won that year came from districts that had a PVI of R+6 or greater. If Democrats won the same percentage of seats from each category this November as Democrats did in 2006, they would net 22 seats — or two seats shy of the 24 they need to win the House. The challenge for Democrats today is to expand the playing field. Of the 26 GOP-held seats in Likely Republican, two have a Democratic PVI, nine have a PVI between R+1 and R+5 and 15 have a PVI of R+6 or greater. Winning just two of those 26 would get Democrats to the magic number of 24 seats.


https://www.cookpolitical.com/analysis/national/national-politics/map-has-changed-math-remains-same