There is no reason to trust any pre-October 2008 polls showing Obama beating McCain, including those now showing him beating McCain by a larger margin than Clinton would. Obama would be the second consecutive Democratic standard-bearer ranked the Senate’s most liberal member by nonpartisan outlets like National Journal. ~John DiIulio

Much of DiIulio’s argument doesn’t persuade, especially the part where he tries to say that Clinton still has a chance, but this part is an important reminder of just how unreliable general election polling is this far away from November.  It’s worth remembering that at roughly this time in the ’04 cycle both Edwards and Kerry polled at least 10 points ahead of Bush with Kerry leading 55-43 and Edwards leading 54-44.  As you may recall, the outcome was rather different.  So polls that show Obama leading nationally by this margin or less are not necessarily reassuring for Obama at all.  I think some of this polling strength reflects the Democratic advantage on the generic ballot, which Obama weakens less because he is less of a known quantity than Clinton right now, and as he becomes better known the effect of that generic advantage will fade.   

If this argument is right, Obama needs to be leading by a much wider margin now to endure the next eight months and the Rezko-Ayers-Khalidi attacks that will be coming his way.  As Mike Pridmore noted at MyDD the other day, Obama’s polling lead over McCain also bears some eerie resemblances to Dukakis leading Bush the Elder in mid-May 1988 (Dukakis was ahead 49-39), including evidence of Republican cross-over support for Dukakis.  The final 1988 result, of course, was Bush 53-45 in what was otherwise a reasonably good Democratic year.  So I’m sticking with my earlier claims.