The Real Magic Number is 1,627?

In 2008, 3,253 delegates will be chosen through caucuses and primaries to represent Barack Obama or Hillary Clinton at the Democratic National Convention.

Once one of the candidates has won a majority of those democratically selected delegates (also known as pledged delegates), the only way his or her opponent could win the nomination is with the support of the 796 unelected, unaccountable superdelegates -- in the process overturning the judgment of the voters.

50%+1 of 3,253 is 1,627. That's the real magic number.

Once a candidate has 1,627 pledged delegates, he or she will win the nomination -- unless the superdelegates step in and reverse the decision of the voters.

At present, CNN estimates 986 pledged delegates for Obama and 924 for Clinton. (John Edwards also has 26.)

That means there are still 1,317 pledged delegates left to be awarded.

Obama must win at least 48.7% of them to hit his magic number.

Clinton must win 53.4% of the remaining delegates to her magic number. In other words, even if Clinton won 53% of the remaining delegates, she would still fall short of a democratically elected majority.

(The numbers aren't perfect mirrors of each other because John Edwards won 26 delegates.)

Later in the day, I'll post some graphs to make this easier to visualize, and tonight voters will select another 176 delegate. After those delegates are chosen, a full two-thirds of all delegates will have been picked.

Obama won the first contest in Iowa and as the calendar winds down, he has led wire-to-wire: from start to finish.

Will he be able to sustain the lead? No one can say for sure.

But one thing is clear right now: Barack Obama is winning.