The Swing States

A Little Math

The further we get into the fall, the more meaningful the state-by-state polls become. But it’s nonetheless useful to bear in mind the hard numbers from past years to keep a realistic view of what the range of possibilties are in any given state. A few months back, I had gone through the Federal Election Commission website and put together a spreadsheet, which I’m only getting back around to now, tallying up all the votes for federal office (President, Senate, House) in the last four election cycles (2000, 2002, 2004, 2006) comprising two presidential elections, four House elections, and a full cycle and a third of Senate races. The chart below lays out the results.

Now, let’s be clear: while the underlying numbers are actual votes cast, basically what I’m doing here is using a metric, not a statistic; I’m combining different types of votes over time in a way that’s not scientific, but rather an effort to take disparate pieces of data and make them digestible. Obviously, there are a host of reasons why this isn’t science: turnout is much larger in presidential years, some incumbents in the Senate and House run unopposed (although this is itself usually a sign of strength), a third of the Senate seats are counted twice here, gerrymandering affects House races, and of course, there’s no fixed way to measure the relative probative value of 2006 results vs. 2000 results in measuring 2008’s political terrain. That said, using three levels of balloting over four election cycles does help give us a large enough sample size to get a look at the real, underlying partisan makeup of particular states, and limit the distorting effects of individual personalities.Here’s the methodology. I present two sets of numbers: “raw” numbers that treat each of the four elections alike, and “weighted” numbers that give a larger weight to more recent results. For the raw numbers, I tallied up all votes cast for each of the two major parties (ignoring third party votes, for simplicity’s sake) in presidential, Senate or House races in 2000, 2002, 2004 or 2006. For the Weighted totals, I weighted the votes by year as follows:

2006=12004=0.752002=0.52000=0.25

i.e., a vote for a House candidate in 2006 was worth twice the weight of a vote for the same candidate in 2002, and four times the weight of a vote for that candidate in 2000.

The final two columns attempt to combine the electoral vote weight of each state with its partisan composition in order to put the closeness of the state in the context of the reward for presidential candidates of swinging it, dividing the number of electoral votes by the square of the margin separating the two parties (the sum is then divided by 100 just for ease of the reader). The equation is:

= (EV/(D%-R%)squared)/100

Without further ado, here is the chart:

State EV D-Tot R-Tot D% (Raw) R% (Raw) D%(W) R%(W) EV/Margin (Raw) EV/Margin (W)
CO 9 6382956 7020832 47.6% 52.4% 49.6% 50.4% 39.74 1752.24
PA 21 20641302 20552361 50.1% 49.9% 51.1% 48.9% 45048.06 469.80
SD 3 1299151 1475882 46.8% 53.2% 50.6% 49.4% 7.40 227.00
FL 27 23291638 25596752 47.6% 52.4% 48.1% 51.9% 121.45 177.99
ME 4 2716999 2607727 51.0% 49.0% 50.8% 49.2% 94.98 147.26
OH 20 18741091 21603342 46.5% 53.5% 47.6% 52.4% 39.74 90.15
NV 5 2666828 2971105 47.3% 52.7% 48.6% 51.4% 17.17 62.81
NC 15 10325146 12013306 46.2% 53.8% 47.1% 52.9% 26.26 43.66
MO 11 10839544 11849293 47.8% 52.2% 47.4% 52.6% 55.54 41.94
MI 17 18610217 16181348 53.5% 46.5% 53.7% 46.3% 34.88 30.36
TN 11 7667830 9245965 45.3% 54.7% 46.6% 53.4% 12.64 23.33
CA 55 50653333 37528032 57.4% 42.6% 57.9% 42.1% 24.83 21.99
NJ 15 13042173 11036751 54.2% 45.8% 54.3% 45.7% 21.62 20.04
WI 10 11604124 10209108 53.2% 46.8% 53.9% 46.1% 24.45 16.24
MN 10 11036669 9639891 53.4% 46.6% 54.1% 45.9% 21.91 14.92
DE 3 1228386 1382643 47.0% 53.0% 47.7% 52.3% 8.60 13.84
TX 34 20096791 28913484 41.0% 59.0% 41.1% 58.9% 10.51 10.66
AR 6 3537401 3099694 53.3% 46.7% 53.8% 46.2% 13.80 10.23
IL 21 20038400 14360894 58.3% 41.7% 58.8% 41.2% 7.71 6.71
WA 11 11697815 9317953 55.7% 44.3% 56.8% 43.2% 8.58 5.88
GA 15 8487883 11830352 41.8% 58.2% 41.8% 58.2% 5.54 5.62
IA 7 4449807 5481142 44.8% 55.2% 44.2% 55.8% 6.49 5.14
OR 7 6478957 5313080 54.9% 45.1% 55.9% 44.1% 7.16 4.99
LA 9 5619749 7391764 43.2% 56.8% 43.2% 56.8% 4.85 4.89
NM 5 2844838 2421980 54.0% 46.0% 55.2% 44.8% 7.76 4.68
VA 13 8614983 12151040 41.5% 58.5% 41.6% 58.4% 4.48 4.59
NY 31 30119490 18450310 62.0% 38.0% 63.8% 36.2% 5.37 4.04
IN 11 7456553 10423416 41.7% 58.3% 41.3% 58.7% 4.00 3.65
KY 8 4718604 6695051 41.3% 58.7% 42.2% 57.8% 2.67 3.31
SC 8 4237672 5992739 41.4% 58.6% 41.4% 58.6% 2.72 2.71
NH 4 1903485 2410498 44.1% 55.9% 43.9% 56.1% 2.90 2.68
MD 10 10555795 7176226 59.5% 40.5% 59.9% 40.1% 2.75 2.53
AL 9 4723688 7403321 39.0% 61.0% 38.8% 61.2% 1.84 1.80
WV 5 3026936 1936042 61.0% 39.0% 58.8% 41.2% 1.03 1.63
AZ 10 4902282 8749386 35.9% 64.1% 37.6% 62.4% 1.26 1.62
MT 3 1512690 1964935 43.5% 56.5% 43.0% 57.0% 1.77 1.53
CT 7 6535475 4380585 59.9% 40.1% 60.8% 39.2% 1.80 1.50
ND 3 1345405 1083121 55.4% 44.6% 57.8% 42.2% 2.57 1.22
OK 7 3435580 5692851 37.6% 62.4% 37.9% 62.1% 1.14 1.20
MS 6 2802212 4604631 37.8% 62.2% 37.4% 62.6% 1.01 0.95
NE 5 2005400 3618693 35.7% 64.3% 38.2% 61.8% 0.61 0.90
UT 5 2255544 4227791 34.8% 65.2% 35.1% 64.9% 0.54 0.56
KS 6 2488872 5157791 32.5% 67.5% 33.4% 66.6% 0.49 0.55
HI 4 2147579 1124171 65.6% 34.4% 65.1% 34.9% 0.41 0.44
MA 12 15605362 4213255 78.7% 21.3% 78.0% 22.0% 0.36 0.38
WY 3 604497 1219602 33.1% 66.9% 35.5% 64.5% 0.26 0.36
RI 4 2146589 1112476 65.9% 34.1% 67.1% 32.9% 0.40 0.34
VT 3 1634826 906494 64.3% 35.7% 65.6% 34.4% 0.37 0.31
AK 3 600268 1394004 30.1% 69.9% 32.8% 67.2% 0.19 0.25
ID 4 1081529 2750657 28.2% 71.8% 28.1% 71.9% 0.21 0.21
DC 3 966738 67883 93.4% 6.6% 93.8% 6.2% 0.04 0.04

A couple of things jump off the list:

(1) Yes, as we all know, Colorado and Pennsylvania are two of the really critical battlegrounds in 2008, and not only at the presidential level.

(2) Some states are genuinely competitive yet never become swing states at the presidential level. Maine has two Republican Senators because they are much more liberal than any national Republican; South Dakota has a Democratic Senator and at-Large Congresswoman because they are much more conservative than any national Democrat, and aren’t running for Commander-in-Chief.