Election Day may be Nov. 6th, but with President Obama grabbing a lead nationally and in key swing states, Americans are already starting to vote.

Idaho, South Dakota, and the crucial swing state of Virginia are the first states to begin early, in-person voting today.

Also today, absentee voting begins in Minnesota, West Virginia, Oklahoma, South Dakota, Georgia, Arkansas, Idaho, and Maryland, bringing the total number of states already accepting ballots to 13. Twelve others -- South Carolina, New Jersey, Maine, Michigan, Mississippi, New Hampshire, Tennessee, Texas, Vermont, Delaware, Louisiana, and Missouri -- will begin absentee or early voting Saturday.

That means, by tomorrow, half the country will be casting votes. By the end of the month, voters in 30 states will be voting already.

More than one-in-three voters – more than 46 million people -- is expected to vote early in 2012 in some form, either in person, by mail, or absentee, according to Dr. Michael McDonald, a professor at George Mason University who studies voter behavior.

“Once you turn up the faucet on early voting, you keep turning it up until it’s all the way open,” said McDonald, who predicts that 35 percent will vote early this year.

Early voting participation has been on the rise in recent election cycles, hitting an all-time high in 2008, when an estimated 30 percent voted early in the presidential election. That was up significantly from 2004, when slightly more than 20 percent cast their ballots ahead of Election Day.

Early voting can, and often does, mean different things in different states.

In 32 states and Washington, D.C., voters can cast their ballots early, in person without any excuse or reason, according to the National Conference of State Legislatures.

In 21 states, like Virginia, voters can vote absentee, but an excuse is required. Some of the acceptable excuses listed on the Virginia absentee ballot application include commuting for 11 or more hours between 6 a.m. and 7 p.m. on Election Day, being away from home due to personal or business travel, or being a student. 

States like Connecticut and New Hampshire do not have early, in-person voting, but do allow voters to return their absentee ballots in person to election officials.

Oregon and Washington State are exclusively vote-by-mail. In 2008, 100 percent of Oregon voters voted by mail or dropped their ballots in boxes at designated locations on Election Day. Washington has been adopting vote-by-mail, county-by-county since 1994, but, in 2011, it went completely by mail.

Colorado has also been moving to vote-by-mail, and, in 2008, four-in-five Coloradans voted that way.

Controversial changes in Florida and Ohio

Early voting laws in several states have also changed in the past four years – and not without controversy, particularly in Florida and Ohio.

In Florida, a state where half of its voters voted early in 2008, the number of days for early, in-person voting has been reduced from 14 to eight (HB 1355) – and voting on the Sunday before the election was eliminated.

Republicans control the governorship and the state legislature, and Democrats have cried foul, especially about the elimination of the Sunday voting. Black churches in particular have made it a point of mobilizing on that day in what’s known as “Souls to the Polls.”

Five of Florida’s 67 counties fall under a national voter-rights law that mandates approval of any changes to election laws by the Department of Justice because of a history of racial discrimination.

The Justice Department approved the measure on the condition that the state keep the early, in-person polling centers in those counties open 12 hours each day, which is the maximum allowed by the state’s constitution.

In July, the Obama campaign filed a lawsuit against Ohio Secretary of State John Husted regarding changes in the state’s early, in-person voting policies.

Legislation, passed in 2011 (HB 194) by a GOP-controlled legislature and signed by a Republican governor, shortened the early, in-person voting period from beginning 35 days before the election to starting 21 days prior.

The legislation also included a provision ending early, in-person voting three days prior to the election for everyone except members of the military. Pressure from local voter’s rights coalitions prompted the legislature to repeal parts of its new voting laws. Senate Bill 295 was passed to repeal specific parts of HB 194, but left intact the provision ending early in-person voting three days prior to the start of the election for everyone except members of the military.

The Obama campaign argued this new law was unfair and violated the equal-protection clause of the constitution. A federal court agreed and ordered the state to restore the three days of early, in-person voting for all voters.

In 2008, Democrats dominated early voting. This time around, McDonald said, Republican presidential candidate Mitt Romney's campaign and Republicans are making a concerted effort to mobilize early voters as well.

“2012 is not going to be 2008,” McDonald said, “so we should expect to see more parity among partisan profiles of early voters.”

Here’s the full calendar of when voting starts in each state:

September:

Sept. 6: North Carolina: Absentee, ends Nov. 6 

Sept. 17:
Kentucky: Absentee, ends Nov. 6
Indiana: Absentee, ends Nov. 6 

Sept. 20:
Wisconsin: Absentee, ends Nov. 6

Sept. 21:
West Virginia: Absentee, ends Nov. 6
Oklahoma: Absentee, ends Nov. 6
South Dakota: Absentee, ends Nov. 6
Georgia: Absentee, ends Nov. 6
Arkansas: Absentee, ends Nov. 6
Idaho: Absentee, ends Nov. 2
Maryland: Absentee, ends Nov. 6
Minnesota: Absentee begins 

Sept. 22:
South Carolina: Absentee, ends Nov. 6
New Jersey: Absentee, ends Nov. 6
Maine: Absentee, ends Nov. 6
Michigan: Absentee, ends Nov. 6
Mississippi: Absentee, ends Nov. 6  
New Hampshire: Absentee, ends Nov. 6   
Tennessee: Absentee, ends Nov. 6
Texas: Absentee, ends Nov. 6
Vermont: Absentee, ends Nov. 6; Early in-person, ends Nov. 5
Delaware: Absentee, ends Nov. 6
Virginia: Absentee, ends Nov. 6  
Louisiana: Absentee, ends Nov. 6  
Missouri: Absentee, ends Nov. 6    

Sept. 27:
Alabama: Absentee, ends Nov. 5
Wyoming: Absentee, ends Nov. 6; Early in-person, ends Nov. 5
North Dakota: Absentee, ends Nov. 5
Iowa: Absentee, ends Nov. 5; Early in-person, ends Nov.5
Illinois: Absentee, ends Nov. 5

October

Oct. 1:
Washington, DC: Absentee, ends Nov 6
Nebraska: Absentee, ends Nov. 6; Early in-person, ends Nov. 5

October 2:
New York: Absentee, ends Nov. 5
Ohio: Absentee, ends Nov. 5; Early in-person, ends Nov. 2* (Secretary of State's website still lists ending Nov. 2, but the court decision would indicate that it would be extended through Election Day.)
Florida: Absentee, ends Nov. 6

Oct. 5:
Connecticut: Absentee, ends Nov. 6

Oct. 8:
California: Absentee, ends Nov. 6; Early in-person, ends Nov.5 

Oct. 9:
Indiana: Early in-person, ends Nov. 5
Rhode Island: Absentee, ends Nov. 6
New Mexico: Absentee, ends Nov. 6
Montana: Absentee, ends Nov. 6
Utah: Absentee, ends Nov. 6 

Oct. 11: Arizona: Absentee, ends Nov. 6; Early in-person, ends Nov. 2

Oct. 12: Alaska: Absentee, ends Nov. 6

Oct. 15:
Colorado: Absentee, ends Nov. 6
Georgia: Early in-person, ends Nov.2 

Oct. 16:
Massachusetts: Absentee; ends Nov. 6

Oct. 17:
Kansas: Absentee, ends Nov. 6; Early in-person, ends Nov. 5
Nevada: Absentee, ends Nov. 6
Hawaii: Absentee, ends Nov. 6
Tennessee: Early in-person, ends Nov.1
Oct. 18: North Carolina: Early in-person, ends Nov. 3

Oct. 19: 
Oregon: Absentee, ends Nov. 6
Washington: Absentee, ends Nov. 6

Oct. 20:
Nevada: Early in-person, ends Nov. 2
New Mexico: Early in-person, ends Nov. 3 

Oct. 22:
Alaska: Early in-person, ends Nov. 5
Arkansas: Early in-person, ends Nov. 5
Illinois: Early in-person, ends Nov. 3
North Dakota: Early in-person, ends Nov. 5
Colorado: Early in-person, ends Nov. 2
Washington D.C.: Early in-person, Nov. 3  
Texas: Early in-person, ends Nov. 2
Wisconsin: Early in-person, ends Nov. 2

Oct. 23:
Utah: Early in-person, ends Nov. 2
Hawaii: Early in-person, ends Nov. 3
Louisiana: Early in-person, ends Nov. 30
Pennsylvania: Absentee, ends Nov. 6 

Oct. 24:
West Virginia: Early in-person, ends Nov. 3   

Oct. 27:
Maryland: Early in-person, ends Nov. 1
Florida: Early in-person, ends Nov. 3 

November

Nov. 2:
Oklahoma: Early in-person, ends Nov. 5

SOURCE: Early Voting Information Center at Reed College