As Alan Abramowitz has pointed out to me in another missive:
Gallup’s new poll in Ohio appears to have the same problem as their latest national poll–there is again a huge discrepancy between their results for registered voters (Bush 48, Kerry 47) and their results for likely voters (Bush 52, Kerry 44). Based on the numbers of registered and likely voters in the Gallup sample, this means that they are projecting that 90 percent of Bush supporters will vote but only 78 percent of Kerry supporters will vote. Again, this seems way out of line with evidence from previous elections and with other polls. In contrast, in Pennsylvania and Washington, Gallup’s results for registered and likely voters are much more similar, and in line with other recent polls.