DOVER, DELAWARE: Victory Math

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What does it take to decide the balance of power in the U.S. Senate? Maybe fewer than 55,000 Delaware votes.

That's what worries top Republican party officials. Here's the logic. Party big wigs in Delaware and nationwide believe that Tea Party Senate candidate Christine O'Donnell cannot win a general election in November. They're convinced that if she gets the Republican nomination today, Democrats will hold the Delaware Senate seat in November. And top Democrats and Republicans agree this seat could keep the US Senate in Democratic hands.

As for the numbers: there are 182,796 registered Republicans in Delaware. In a hotly contested primary in 2008 the state saw a high 28% turnout. This race has garnered a lot of media attention so even if the turnout is 30% that's 54,838 voters. My producer points out: that's about the number of people who attend a college football game. So following that logic, a stadium size group of voters today could potentially determine who controls the US Senate in November.