Now that Rick Santorum has officially suspended his campaign for the Republican nomination the media is sure to turn its attention to the 'horse race' between President Obama and Mitt Romney. While I certainly question the usefulness of polls conducted 7 or more months prior to election day, I also recognize that previous political science research indicates most voters have already decided for whom they will vote in November. For voters who have made their decision, the issues no longer matter on a daily basis, thus why should the media cover them if their reporting is for the bulk of their audience? In some ways it would be similar to a caller of a horse race announcing the past performances of the entrants in a race after the bettors have made their wagers and the horses have left the starting gate. If the media are just providing an update on the status of the race to voters who have already made up their minds, the horse race coverage may make sense as Andrew Gelman argues. To be sure, though, there are a small percentage of voters who will make up their minds later in the campaign, as the classic book The American Voter reported in 1960 (and has been confirmed by American National Election Studies every two years since).
All that is to say that the polls the media are reporting today won't tell us much about who will ultimately be elected president in November. Polling conducted after Labor Day will give us a much better picture. The polls do, however, provide us with a pretty good idea of the floor and ceiling of support for each of the party nominees. Since 1932, the largest margin of victory for a presidential candidate was 24.3% (FDR's landslide reelection in 1936), while two others enjoyed victories by at least 20 percentage points (LBJ in 1964-22.6%; Richard Nixon in 1972-23.2%). Most presidential elections are relatively close with margins of 5-8 percentage points. This year is likely to be no different. Having said that, today will be the first of an ongoing series of posts that will be updated whenever a new national poll by a reputable polling organization is released. I will include results from ABC, CBS, NBC, Fox, Pew, USA, and CNN (and each of their respective partners).
So, in the classic style of my favorite race caller the great Trevor Denman, 'away they go.'