Inside the mind of a Superdelegate

(CNN) -- Democratic Sen. Sherrod Brown of Ohio is one of the undecided superdelegates being courted persistently by the campaigns of Sens. Hillary Clinton and Barack Obama.

With the race for the Democratic presidential nomination so tight, it's becoming increasingly likely that superdelegates like Brown could determine the outcome.

Superdelegates are a group of about 800 party leaders and officials who cast their votes at the Democratic National Convention. They are free to vote for the candidate of their choice.

Brown, a freshman senator, says Clinton called him immediately after her decisive win in Ohio's primary and asked for his support. Obama has called as well. Watch Brown explain his thinking »

Brown's not saying who he'll endorse, but in an interview with CNN, he talked about what's important to making his decision.

"I weigh several things. I weigh who won my state, I weigh what issues they are talking about and how they're talking about those issues. I weigh how these candidates are doing nationally on delegate count and how they're doing nationally in popular vote," Brown said.

Right now, Obama leads in the overall delegate count, with 1,527 to Clinton's 1,428. But Clinton has the support of more superdelegates, based on those who have publicized their pick. Clinton's received the backing of 238 superdelegates, compared with Obama's 199. See how the delegate race might play out »

A candidate must get 2,024 delegates to clinch the Democratic nomination.

Brown said momentum is also a factor in making his choice, and he held out hope that the decision for superdelegates would be easier after the next big primaries because a clear front-runner would emerge.

"I don't think this is going to go down to a backroom deal; nobody wants to overturn what voters have said," Brown said.

The superdelegate setup was established in 1982 to bring more moderate Democrats back to conventions, where their attendance had been dropping since the 1950s, and to reflect the party's mainstream more accurately.

The first campaign to benefit from the roles of superdelegates was that of former Vice President Walter Mondale in 1984. His 1984 campaign went into the party convention with too few delegates to secure the nomination against the campaigns of former Sen. Gary Hart and Jesse Jackson.

Mondale had received more votes, but Hart had won more states. Mondale was able to line up the superdelegates going into the convention and avoid a fight on the convention floor.

While divided over which candidate to support, Democrats largely agreed that the battle over delegates needs to be resolved without a sense that superdelegates are making a decision that opposes what voters want.

"I do expect that this will be worked out prior to August, prior to the Democratic convention in Denver," Brown said. "I don't know when my personal decision will come or how this will all unfold. It's all been so unpredictable so far."

Brown admits he has wavered between the two candidates. But when pressed on which one he's leaning toward supporting, he wouldn't say.

And how did he vote in the Ohio primary?

"My daughters and my wife are the only ones who know."