(CBS News) COLUMBUS, Ohio - The date the federal government set for the presidential election is five weeks from Tuesday, but many of the states are getting a head start.
Voters in Ohio, one of the key battleground states that will determine which way this election goes, began casting their ballots. That brings to eight the number of states where voting is under way. Thirty-four states in all will begin voting before November 6th.
The latest pre-election polling in Ohio -- the second-biggest battleground state -- shows President Obama with a 10-point lead over Mitt Romney, 53 percent to 43 percent.
Back in 2008, nearly 30 percent of Ohio's more than 7 million voters cast their ballots before Election Day. This time around the campaigns would love to see them increase that percentage.
What some are calling election month began in Ohio promptly at 8 a.m. Some voters had overnighted in the parking lot outside a Columbus polling place.
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Emerald Hernandez was there bright and early.
"For me it's a convenience. I can come in and get it done," Hernandez said. "I can say once in my life I've camped out to vote.
The names of the early voters are reported by the county board of elections --not their votes, just their names. The campaigns try to guess how they voted base on where they live or past voting history.
"You can make assumptions based on one's surname: O'Connor, O'Brien, for instance," Chris Redfern, chair of the Ohio Democratic Party. "If you have an Irish surname, you're probably a member of a Catholic Church. We can look at the local parish and whether or not that parish is more conservative or more progressive."
Scott Jennings, who runs the Romney campaign in Ohio, said campaigns often act on what they learn.
"You can make decisions based on who's voted and who hasn't on where you put your dollars, where you send your mail, where you do your phone-calling and where you do your door-knocking," Jennings said. "So, if I know you've already voted the first week of October, I'm not going to send you direct mail three days before the election. It would be a useless exercise."
In a close election, no campaign wants to spend time and money on anyone other than the so-called persuadable voters who will be getting plenty of attention over the next five weeks.