Why Kerry Cannot Win Ohio -- or, what I learned in 7th grade algebra.

It's the morning after election, and Kerry has withheld conceding, as Ohio counts absentee and provisional ballots (which, by law, they must due within 12 days, so watch for Nov 13).

Kerry is separated from Bush by 140,000 votes in Ohio. There are estimated to be N=175,000-250,000 provisional ballots, and tens of thousands of absentee military ballots. To overcome this deficit, Kerry needs to win a fraction f of

fN>140,000 + (1-f)N
(2f)N>140,000+N
f>(140,000)/(2N) + 1/2
f> 1/2 * (140,000/N + 1)

Thus, for the lowball estimate (175,000), Kerry needs f=90% of the uncounted ballots. If there are as many as 250,000, Kerry needs 78%.

It's possible Kerry pulls down that percentage -- many of the provisional ballots are in heavily Democratic areas, because of the Republican challenges, and Kerry is right to not concede this election Ohio makes its official declaration. But in a state that's 50-50, pulling out a population which is 78% Kerry would be lucky, indeed.