If you really want to delve into election stats, the 1948-2016 National Election Studies provides tables and graphs that display the ebb and flow of public opinion and electoral behavior and choice in American politics since 1948.

Dave Leip's maps of election results on a national and state by state level.

Official vote counts for federal elections from the official sources among the various states and territories, 1920 through 2010.

Animated maps showing changes over time in voting patterns. From the University of Richmond.

Roper Center's tutorial on the fundamentals of public opinion polling, including easy definitions of sampling, survey error, etc.

Roper Center's how-to page for interpretive analysis of survey data explains how to read evidence from public data in a fair, non-biased manner.