What Past Election Results Tell Us to Expect This Time

There’s no shortage of opinions on how the 2012 U.S. Presidential Election will turnout, and a lot of the disagreement  comes from the different landscapes presented by the National and State polls.  Romney supporters are encouraged by clear and substantial leads in the Gallup, Rasmussen, ABC News/Washington Post, and NPR polls.  Obama supporters point to the CBS News/NY Times and Politico polls, but they also point to the state polls, observing published leads for Obama in Iowa, Ohio, Wisconsin, Minnesota, Michigan, Nevada, New Hampshire, New Mexico, and Pennsylvania.  There’s too many states on Obama’s side, they say, for Obama to lose.  The problem is, the math just does not work.  Either most of the national polls are wrong, or most of the state polls are wrong.  And things just get messy from there.

There’s all kinds of anecdotal stories to read and hear, but there’s also a record we can check.  Generally, there is a relationship between how a candidate does nationally and how he does in a given state.  As his national support rises, his support in each state rises to some degree, not at the same rate of course but the better a candidate does nationally, the states have to reflect it.  So we can look at past state results in relation to national results, to give us an idea of what should happen.  To keep it simple, for here I will just address battleground states.

First, to identify the battleground states.  I disagree a bit with RCP, I don’t think anyone can seriously pretend that Arizona, Missouri, or Oregon are in play this year, but I will take the rest:   Colorado, Florida, Iowa, Michigan, Minnesota, Nevada, New Hampshire, North Carolina, Ohio, Pennsylvania, Virginia and Wisconsin.  Here’s how each state performed, by party, relative to the national election results for the last four Presidential elections:

Colorado:  Democrat candidates average 2.81 points lower in Colorado than their national support, while Republican candidates average 2.01 points higher in Colorado than their national support.

Florida:  Democrat candidates average 0.97 points lower in Florida than their national support, while Republican candidates average 1.61 points higher in Florida than their national support.   Also, Republicans ALWAYS produced slightly higher results in Florida than their national support.

Iowa:  Democrat candidates average 0.80 points higher in Iowa than their national support, while Republican candidates average 0.62 points lower in Iowa than their national support.   Also, Democrats ALWAYS produced slightly higher results in Iowa than their national support.

Michigan:  Democrat candidates average 3.20 points higher in Michigan than their national support, while Republican candidates average 2.90 points lower in Michigan than their national support.   Also, Democrats ALWAYS produced slightly higher results in Michigan than their national support.

Minnesota:  Democrat candidates average 1.35 points higher in Minnesota than their national support, while Republican candidates average 3.26 points lower in Minnesota than their national support.

Nevada:  Democrat candidates average 1.45 points lower in Nevada than their national support, while Republican candidates average 0.16 points higher in Nevada than their national support.

New Hampshire:  Democrat candidates average 0.44 points higher in New Hampshire than their national support, while Republican candidates average 1.02 points lower in New Hampshire than their national support.

North Carolina:  Democrat candidates average 4.56 points lower in North Carolina than their national support, while Republican candidates average 6.31 points higher in North Carolina than their national support.   Also, Republicans ALWAYS produced slightly higher results in North Carolina than their national support.

Ohio:  Democrat candidates average 1.21 points lower in Ohio than their national support, while Republican candidates average 0.92 points higher in Ohio than their national support.   Also, Republicans ALWAYS produced slightly higher results in Ohio than their national support.

Pennsylvania:  Democrat candidates average 1.60 points higher in Pennsylvania than their national support, while Republican candidates average 1.49 points lower in Pennsylvania than their national support.

Virginia:  Democrat candidates average 2.76 points lower in Virginia than their national support, while Republican candidates average 3.67 points higher in Virginia than their national support.   Also, Republicans ALWAYS produced slightly higher results in Virginia than their national support.

Wisconsin:  Democrat candidates average 0.95 points higher in Wisconsin than their national support, while Republican candidates average 1.80 points lower in Wisconsin than their national support.

What this tells us, is the likely result of three different conditions in the national popular vote:

If Barack Obama wins the Popular Vote, he will definitely win Iowa, Michigan, Minnesota, New Hampshire, Pennsylvania, and Wisconsin, and would likely win Nevada and Ohio .  Romney could still claim Colorado, Florida, North Carolina and Virginia but that would not be enough.  Obama would win re-election by 281 EV to 257.

If Romney wins the Popular Vote with 51.5% or more, he could win all of the battleground states but Michigan; that state seems out of reach in any scenario.  That could mean a Romney win by an Electoral  margin of  331 EV to 207.

If the two candidates are essentially tied in the Popular Vote, Obama would claim Iowa, Michigan, Minnesota, New Hampshire, Pennsylvania and Wisconsin, while Romney would claim Colorado, Florida, Nevada, North Carolina, Ohio, and Virginia.  That would produce a 281-257 Electoral win for Romney.

The actual results will be sure to include some changes from the script, of course.  I think, for example, it’s more likely this year that New Hampshire would go to Romney and Nevada would go to Obama than vice versa, but we shall see.  The point is that the last several elections do give us an idea of how things turn out relative to different levels of polls and voting, and that’s something to keep in mind.

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