Wednesday, April 19, 2006

Senate Races and Presidential Approval in the States

(Click on figure for a larger view.)

President Bush's approval ratings have fallen over the past 12 months in all the states, though from different starting points and at somewhat different rates. For tossup and close Senate seats, these trends tend to favor the Democrats on balance. The state trends in Pennsylvania and Rhode Island are particularly unfavorable to Republicans, though Maine's Olympia Snowe seems untroubled by equally bad presidential trends.

In the graph above, the horizontal axis is my estimate of state level approval of President Bush in May of 2005, based on SurveyUSA's 50 state tracking poll. (See my previous post on these trends here for background and trends within states.) This estimate is based on the entire 12 months of data from the state, so my "estimated approval" does not exactly match SurveyUSA's poll results. The linear trend in approval is plotted on the vertical axis. This is the estimated percentage point decline PER MONTH in approval of the president. You can mentally multiply this by 12 to get the estimated decline over the past year. For example California has decline rate of -.6 so this implies a year-long drop of -7.2%.

I should add that MANY of these state differences are not statistically different from one another, so this plot should be taken with a substantial lump of salt. If we said all states declined at a -.59% per month rate, we wouldn't be far wrong. (-.59 is the estimated rate of decline using all states and forcing them all to have the same rate of decline. One cannot reject this common rate of decline using a standard fixed-effects model.) Nonetheless I'll treat these differences as at least somewhat indicative of state trends (and risk the potential error.)

The Senate seat ratings are taken from the Cook Political Report for March 31
. I've called his "Solid" and "Likely" races as "safe" here. "Tossup" and "Leans" are the same as Cook's categories.

The unambiguously good region for the Republicans is the top right quadrant. These states are above the average May 2005 approval rate (45.3%) and have declined in approval at a slower rate than other states. (Again, be careful-- as you come close to the center none of these differences are statistically significant.) Four safe Republican Senate seats are here: UT, MS , AZ and VA. One Democratic seat, WV, is also in this quadrant (barely). Likewise the tossup seat in TN is near the center but in this quadrant. That isn't great news for TN Republicans, but it certainly beats being in the lower left quadrant.

The lower left quadrant is unambiguously good for Democrats. States here are below average in initial presidential approval AND have declined at a greater than average rate over the past year. Here two Republican Senate seats in PA and RI are tossups and in unfavorable conditions. (They are also in "blue" presidential states, indicated by the outer color of the point.) Maine's Snowe is also here, but she seems immune from the force of presidential approval. What is good news for the Democrats here are the "leaning" races in NJ, MD and MI. The national forces are working to reinforce the Democratic campaigns in these three important states. MN is a tossup open-Dem race with average initial approval but somewhat stronger than average decline in approval. As with Tennessee, that ain't great, but better for the Dems than if this state were up and to the right.

The ambiguous quadrants are top left--- below average initial approval but slower rate of decline--- and the bottom right--- above average initially but with faster decline. The VT and WA races Lean Dem in the top left. VT has some of the lowest approval ratings in the country, so that favors the Dems. WA is closer to the center, not so far from the average state. The Republican tossup in Missouri is also very close to the center, as is Florida's seemingly safe Democratic seat. Ohio's tossup also suffers from the low initial approval but the state Republican party troubles probably matter more there.

The bottom right quadrant suggests added problems in Montana which is already a tossup. While approval started at a well above average 54%, it has fallen at one of the two fastest rates in the country and now stands at only 40% as of April. The Nebraska "leans-Dem" seat is more ambiguous with closer to average decline and a higher initial approval rating. Nebraska is one of only four states with approval still above 50%. Other races in this quadrant appear safe regardless of party.

Of the tossup races, PA and RI clearly face strong anti-Republican national forces. I'd add MT even though that state is in the lower right quadrand. MT has fallen to the 17th most supportive state for President Bush, but with only a 40% approval rating in SurveyUSA's April poll. That rate of decline seems to bode ill for Republican candidates.

The tossups in MO, TN and MN are all closer to the average across the country, neither particularly helped or hurt by national forces relative to other states. (Of course, the overall level of presidential approval is a national drag on the Republican's right now, so this isn't to say they are helped by national forces, just not hurt more than average.) The Ohio tossup has a lower than average decline, but still OH has a slightly below average 34% Bush approval rating, on top of the local troubles.

Of the "leaning-Dem" races, NJ, MD and MI seem to clearly benefit from national forces, and I would add VT. WA is close to average (current approval 38%, slightly above the national average of 36% in the SUSA April poll.) Only Nelson's Nebraska seat leans Dem into the face of national winds.

The Democrats look fairly good in their "leaning" races. Of the tossups, Republicans have more disadvantages than advantages with RI, PA, MN and MT looking worst. TN, MO and OH relatively better but not great. But these are national forces-- as always, the local race and the local candidates will have a lot to say about the final outcomes (not to mention the local voters!)

Control of the Senate looks like it could be a close thing. Dems have more exposure but Reps have more tossups and generally less favorable state trends. Stay tuned.

Data: The Cook Political Report here provides ratings of all Senate Races. The 50 state presidential approval data is from SurveyUSA here. They generously provide free access to their unique approval data at the state level. The sponsors of these surveys, listed below, are the ultimate reason we have these data. Thanks.

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Alabama WKRG-TV
Alaska SurveyUSA
Arizona KPNX-TV
Arkansas KTHV-TV
Colorado KUSA-TV
Connecticut WABC-TV
Delaware WCAU-TV
Hawaii KHON-TV
Idaho SurveyUSA
Illinois KSDK-TV
Kansas KWCH-TV
Louisiana SurveyUSA
Massachusetts WBZ-TV
Mississippi SurveyUSA
Missouri KSDK-TV
Montana SurveyUSA
Nebraska SurveyUSA
Nevada KVBC-TV
New Hampshire WBZ-TV
New Mexico KOB-TV
North Carolina WTVD-TV WFMY-TV
North Dakota SurveyUSA
Oklahoma KFOR-TV
Oregon KATU-TV
Pennsylvania WCAU-TV
Rhode Island WLNE-TV
South Carolina WCSC-TV WLTX-TV
South Dakota SurveyUSA
Tennessee WBIR-TV
Vermont SurveyUSA
Washington KING-TV KATU-TV
West Virginia WUSA-TV
Wisconsin WDIO-TV
Wyoming SurveyUSA