Can I just note that I seem to live in some kind of mirror universe where the fact that Barack Obama has, for months, maintained a modest lead over John McCain in every public poll constitutes bad news for Obama and that the specific reason it constitutes bad news for Obama is that the larger political climate is favorable to Obama. The trouble of course is that given the favorable climate the expectation is that Obama will lead, so in order to "really" win, he needs to win by some gigantic margin -- merely being the first Democrat in over thirty years to secure a majority doesn't cut it. Or something.
But wouldn't it be interesting to visit an alternative reality in which the goal of a campaign is to win the election rather than to beat arbitrary media expectations? In this world, a modest-sized but stable and consistent lead would count as an indication that you're winning. And the existence of favorable background conditions for your candidacy would assuage doubts that the lead is likely to vanish over time.