While the polling average in Nevada still shows a close race (Obama +3.0), Democrats have a history of over-performing on Election Day in the Silver State. Going back to 2004, the polling  predicted a comfortable 6.3 win for George W. Bush. Bush would win Nevada, but by less than three points. In 2008 the polls also showed Barack Obama winning by about six points, but his final margin of victory exceeded 12 points. Finally, in 2010 polls predicted a 2.7 point win for Republican Sharon Angle. Harry Reid’s 5.6 point win over Angle represented an 8.1 point difference between the polls and actual performance.

The reason for the difference is usually credited to the Democrat’s superior turnout efforts. Democrats have a strong union infrastructure that allows them to turnout casino workers and other blue collar constituents. This year does not appear to be any different for Republicans. The GOP has been marred this season by in-state fighting after Ron Paul supporters took control of the state party apparatus. The state’s relatively high Mormon population may help, but will likely not be large enough to offset traditional Democratic advantages.

If Republicans expect to win Nevada they will likely need to see a poll margin of at least a couple of points to offset the Democrat’s operational advantages. As the polls currently stand it looks like the President is headed towards a victory by at least five points.