GOP pollster Ayres calls it a risk worth taking.

"If you are Team Romney you expand the map," Ayres said. "Money flows with momentum, and there will be no shortage of it if he looks like a potential winner. Romney needs multiple ways of getting to 270 (electoral votes), and expanding the map significantly increases his chances."

Top Romney advisers are waging a spirited internal debate on this question.

"Tempting, but may be mirages," one top outside adviser told CNN. Another said polling conducted after the second presidential debate would be more determinative.

The flip side of this is whether the Obama campaign needs to spend to defend states they just days ago believed were safely in their path to 270.

"No big tricks," the outside Romney adviser said of the strategy for Tuesday's debate. "We like viewers getting to see them side by side."

The same "Presidential DNA" test that makes many Republicans skeptical about making major investments in Michigan and Pennsylvania is the source of increasing optimism about the overall path to 270.

Romney is now in dead heats or better with the president in Nevada, Colorado, Iowa, Ohio, Virginia, North Carolina, and Florida.

Obama carried all of those states in 2008. But all of them were Republican red for president in 2004, and all but Iowa in that list also voted Republican for president in 2000.

"If you had told us a year ago that we would be three weeks out and in a jump ball race with a personally popular president and the outcome hinged on winning states that are traditionally GOP in presidential years, we would have taken that scenario in a heartbeat," the senior Romney adviser said. "Well, here we are. This is a great election."