Drilling down, Obama trails by just 7 points among white men and 6 points among white women -- groups that Kerry lost by 25 points and 11 points, respectively, in 2004.
Again, that relies in large part on Obama's relatively strong showing among white men (Obama +5) and white women (Obama +11) who name the economy as their top voting issue.
Similarly, Obama has an unusual 4-point edge among mainline or non-evangelical white Protestants, a group George W. Bush won by 11 points in 2004.
The reason is the same: Among mainline white Protestants who cite the economy as their top issue, Obama leads McCain by a wide 59-38 percent. Those who pick other issues favor McCain, 55-41 percent.
Results are similar among white Catholics, married women, married men, seniors, working-class and middle-class whites: In each of these groups, Obama does far better among those who say the economy's the issue driving their vote.
Indeed, even among evangelical white Protestants, one of McCain's single best groups, those focused on the economy are twice as apt to support Obama, 29 percent vs. 14 percent. And Obama wins 16 percent support from Republicans who cite the economy as their top issue, compared with 7 percent from those who don't.
McCain's also had no traction on taxes, "Joe the Plumber" or no; Obama's held a steady lead, now 9 points, in trust to handle them -- the first Democrat to lead on taxes since Bill Clinton's victory in the economy-driven election of 1992.
And Obama's withstood McCain's questions about his readiness; the two remain about even in trust to handle a crisis, 49-46 percent, Obama-McCain.
Other measures across the three weeks of this ABC/Post tracking poll have indicated Obama's ability to clear the "experience" hurdle; 55 percent say he's experienced enough to serve effectively as president and 56 percent call him a "safe" rather than "risky" choice for president – more than the 51 percent who say so of McCain.
McCain's had more difficulties clearing his hurdles.
Fewer than half last week, 47 percent, thought he would lead the country in a different direction than Bush, a problem given Bush's 23 percent approval rating. Never in the campaign has McCain managed to cross the 50 percent mark on offering a new direction.
As reported Monday morning, while 21 percent call the race of the candidates an issue in their vote, more, 48 percent call the candidates' age an issue -- and concern about age works against McCain in a way that concern about race does not.
Age concerns also exacerbate the Palin problem; 44 percent of all likely voters say her presence on the GOP ticket makes them less likely to support McCain. That's risen sharply since September -- and among those concerned about the age of the candidates, it jumps to 61 percent.
Obama leads among men and women alike in this poll, with no significant gender gap; that's a change from the last three elections, in which Democratic candidates won women but lost men (Clinton by a scant point in 1996). The last Democrat to win men and women alike was Clinton in 1992; the last Republican, George H.W. Bush in 1988.
Obama's lead among single women, a core Democratic group, is similar to Kerry's in 2004, but he's doing better with single men, and especially with married men and women alike -- again, with the economy as the motivator.