Early voting is more about locking down the votes of hard-core supporters than drawing in independents and undecided voters, strategists from both parties said. The goal is to "bank" those votes in order to target undecided voters later.
"There's a whole bunch of basically diehard Democrats who will show up on Election Day no matter what; that's their ritual," said Doug Kelly, executive director of the Ohio Democratic Party. "But there's another group that is really important."
That group includes first-time voters in 2008, who may not vote in a midterm, and "average folks" with busy schedules who need a push to get to the polls and would appreciate the convenience of early voting, he said
Party strategists in Washington and in battleground states said they believe that early voting will increase the number of Americans who participate in elections.
"Every time you have that happen," Kelly said, "it's a good thing for democracy overall."
ABC News' Michael Falcone and Amy Walter contributed to this report.