JEFFERSON CITY — Election Day is approaching, but there's no need to wait. In many states, you now can vote early.
Yet what's a convenience for you is increasingly an opportunity for political gamesmanship to the candidates on the ballot.
In key swing states, Democrats and Republicans are battling this year to gain even the slightest electoral advantages by tinkering with the times, dates and places where people can vote early. Their sights are set not only on this year's gubernatorial and congressional campaigns but also on an even bigger prize: control of the White House after the 2016 elections.
Republican-controlled legislatures in Missouri, Ohio, North Carolina and Wisconsin have all taken recent steps to curtail early voting by limiting the days on which it's available.
Meanwhile, Democratic-led legislatures have passed measures expanding early voting or instant registration in Hawaii, Illinois, Massachusetts and Minnesota. And Democratic activists in Missouri are backing an initiative petition that could create one of the nation's most expansive early voting systems.
The efforts all are born from a shared political assumption.
"For whatever reason, both sides seem to believe that increased early voting will help Democrats and hurt Republicans," said David Kimball, a political science professor at the University of Missouri-St. Louis who studies voting.
New research suggests that those partisan assumptions about early voting might not be true. Yet the perception is deeply grounded because of President Barack Obama's pioneering use of early voting to drive a greater number of Democrats to the polls in his victories in 2008 and 2012.
At least 33 states now have laws that allow people to vote in person before elections without needing an excuse to obtain an absentee ballot. Early voting laws became increasingly common after the disputed 2000 presidential election as a means of diminishing long Election Day lines that had frustrated voters.
But Democrats were especially aggressive in seeing the potential for their get-out-and-vote efforts. In 2008, for example, some Democratic-aligned groups drove worshippers from predominantly black churches straight to early voting sites in what became known as a "souls to the polls" campaign.
Following his re-election in 2012, Obama's campaign reported being especially successful at getting their "sporadic supporters" to vote early. In many states, Republican Mitt Romney won a majority of Election Day votes but couldn't overcome Obama's lead in early balloting, the report said.
The Republican National Committee concurred in its own post-election analysis that early voting "had a significant impact on the outcome of the election."
Republicans now are trying to use their control of pivotal state capitols to pare back those early voting laws. North Carolina Gov. Pat McCrory signed a law last year to reduce the early voting days from 17 to 10 and eliminate same-day registration. The changes are being challenged by both the American Civil Liberties Union and the U.S. Justice Department, which contends the changes disadvantage blacks who tend to vote early more often.
Also being challenged are Republican-backed policies in Ohio that prohibited early voting on Sundays or during evening hours. A new Wisconsin law allows early voting only on weekdays.
Tweaking the voting times "has become kind of a partisan game," said Mike Brickner, senior policy director for the ACLU of Ohio.
That partisan jostling is particularly evident in Missouri, where Democratic-aligned groups are pushing for a six-week early voting schedule that specifically includes weekend hours and multiple voting locations. The initiative campaign's treasurer is a former staff member of Democratic Attorney General Chris Koster, who plans to run for governor in 2016.
After a Republican consultant called the plan a "major liability for Republicans," the GOP-led Legislature countered with a proposed six-day, no-weekends schedule that limits early voting to local election offices.
Missouri Senate President Pro Tem Tom Dempsey said Republicans fear a long early voting period would be "incredibly expensive" for local election clerks and "could be highly manipulated" by Democrats.
Early voting generally increases voter turnout by 2-4 percent, which is statistically significant, said Paul Gronke, director of the Early Voting Information Center at Reed College in Portland, Ore.
Some of the assumptions about early voting have been challenged by recent research at the University of Wisconsin-Madison. Professors there found early voting that diminishes the publicity surrounding the actual election day can hurt turnout and ultimately aid Republicans. But they found that when early voting is coupled with same-day registration, the advantage shifts to Democrats.