This, of course, will change. But these are the numbers, as of September 3, 2012, 4 PM Eastern time:
46.4% apiece. Below is the last month or so, with August 21st (a week before the convention) picked out for further contrast.
A good number of people are trying to argue that there was no Romney ‘bounce’ from the convention. This is… interesting. But the truth of the matter is that this is the first time that the two candidates have been tied since the middle of October if 2011. So: if the convention and the Ryan pick (which was also dismissed by the chattering classes) didn’t cause the race to tighten in Romney’s favor… what, exactly, did?