SOUTH BEND — Sen. Hillary Clinton and Sen. Barack Obama have one month to reach six million voters before the May primary.

Obama's campaign has already started broadcasting TV ads throughout Indiana.

And Clinton's aren't far behind.

Experts say the impact of the TV ads remains to be seen because Obama is taking a unique, personal approach. Experts say it allows voters to get to know Obama without making dozens of visits to Indiana.

Two candidates. Two strategies. One goal.

Clinton has made 28 stops to 18 Indiana cities.

Obama has only made two, but he's the first one into living rooms.

"Her focus is on getting out and talking to as many Hoosiers as possible," said Jonathan Swain, an Indiana spokesperson for Clinton's campaign. "Sen. Clinton is committed to getting to every part of the state."

"Part of the strategy really is just part of a comprehensive strategy to introduce Sen. Obama to Hoosiers, to get to know who is he and what he plans to do," said Nick Kimball, an Indiana spokesperson for Obama's campaign.

Notre Dame professor and media columnist Ted Mandell watches the ads online. He realizes both candidates have 31 days to reach out to six million Hoosiers, so candidates must use ads.

"You can't shake millions of people's hands," said Mandell.

Obama's TV ads started this week, and Clinton's will start Tuesday. And even the ad strategies are different.

Clinton's ads use a narrator to convey one message that viewers will remember. Whereas, Obama's take a personal approach, so they remember him.

"He speaks directly to the voter. It's an effective ad. In some ways, it takes the place of him visiting a town in Indiana because he is talking directly to the viewer, " said Mandell.

But Mandell says no matter how effective the ad or the speech is, campaigning involves simple tricks.

"You are not really getting the candidate. You are getting an image of the candidate," said Mandell.

Clinton's campaign is trailing far behind Obama in fundraising. She's raised $70 million, $20 million in March.

Obama raised twice as much money in March, bringing his total to $131 million. That's allowing Obama to spend more money on TV advertising in most states.