The Literary Digest Survey

The Literary Digest is almost certainly best-remembered today for the circumstances surrounding its demise. It conducted a "straw poll" regarding the likely outcome of the 1936 presidential election. The poll showed that the Republican governor of Kansas, Alf Landon, would likely be the overwhelming winner. This seemed possible to some, as the Republicans had fared well in Maine, where the congressional and gubernatorial elections were then held in September - as opposed to the rest of the nation, where these elections were held in November along with the presidential election, like today. This seemed especially likely in light of the conventional wisdom, "As Maine goes, so goes the nation", a truism coined because Maine was regarded as a "bellwether" state which usually supported the winning candidate's party.

http://en.wikipedia.org/wiki/The_Literary_Digest
http://historymatters.gmu.edu/d/5168/
http://faculty.muhs.edu/kresovic/MT177/assignments/05/Squire.pdf