The latest voter registration numbers in Iowa illustrate why this state is a battleground in the presidential election.

As of November 1, 2012, there were 629,443 Iowans who registered to vote as Republicans and 628,043 registered Democratic voters.

In 2008, as a result of historic Iowa Caucus turnout, about 60,000 voters registered as Democrats that night, giving Democrats a sizable edge. But Republicans started chipping away at that in 2010. By June of this year Republicans had surged to a 21,000 voter registration edge in Iowa. That has essentially evaporated, down to a narrow 1,400 edge for Republicans. 

Add the “no party” or independent voters to the totals for Republicans and Democrats and more than 1.9 million Iowans had registered to vote by last Wednesday. That’s below voter registrations in Iowa for the 2004 and 2008 presidential elections. Iowa has “same-day” voter registration, however, so the total will change based on those who register to vote at their polling place on Tuesday.