Obama's lead among voters making less than $35,000 per year remains substantial at a little over 70 percent. But McCain, who had previously scored well only with the highest income brackets, now holds slight leads among voters in all income groups starting at $35,000 and above.
"You've got to think that it is tax-and-spend that concerns them. Is McCain starting to connect with the middle class?" Zogby said.
Obama still had solid, if slightly diminished, leads among two important groups which could play pivotal roles in the November 4 election. Among independents he had a 14 point lead, down from a peak of 29 points. Women also still backed Obama by a 14-point margin, down from 20 points late last week.
McCain, who once had a 4-point deficit among male voters, now has a 4-point lead at 48-44 percent. And whites back McCain by a 12-point margin, up from 6 points on Friday.
This type of drop for Obama and rise for McCain over the last week might be one reason why John McCain feels confident enough to "guarantee victory" in his latest interview with NBC's “Meet the Press”.