Story highlights In 2008, Barack Obama swept Nebraska, Kansas and several rural states with caucuses, racking up victories that fortified his delegate lead.

For Clinton, it was a profound mistake that helped make it impossible to overtake Obama in the epic fight for delegates.

Both Bill Clinton and Chelsea Clinton visited Nebraska this week

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Lincoln, Nebraska (CNN) Hillary Clinton learned many lessons from her first presidential campaign, but perhaps one of the biggest can be felt here on the eve of the Democratic caucuses: Delegate math.

The Clinton campaign is not projecting the image of fighting hard to win Nebraska -- her only visit came last December -- but it is fighting hard to prevent a blowout in this and other small states holding contests this month.

In 2008, Barack Obama swept Nebraska, Kansas and several rural states with caucuses, racking up victories that fortified his delegate lead. For Clinton, it was a profound mistake that helped make it impossible to overtake Obama in the epic fight for delegates.

So with a share of Nebraska's 25 delegates in mind, aides dispatched former President Bill Clinton to Lincoln and Omaha on Friday, a visit that sent Democrats buzzing in this deeply conservative state. His trip came after a two-day stop earlier this week by Chelsea Clinton.

The Clinton campaign -- keen on not raising expectations here -- did little to promote an endorsement from the state's largest newspaper. The Omaha World-Herald, now owned by Warren Buffett, praised Clinton as a "stronger choice" than Bernie Sanders.

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