he says, "because that region is still competitive for both parties, other than Illinois."

That may be bad news for Romney. States such as Michigan, Wisconsin and Pennsylvania have not supported a GOP presidential nominee since 1988. Still, as Ayres points out, each elected Republicans to statewide office in 2010.

But the industrial states in and around the Midwest serve to illustrate the point: Republicans at the presidential level have not been able to carry enough large states to win any but narrow victories since the 1980s.

George W. Bush hit the GOP's recent high-water mark in 2004 with just 286 electoral votes out of 538. In his 2000 victory, he collected 271 — just one more than the minimum needed to win.

By contrast, Obama and Bill Clinton each won atleast 365 electoral votes with their winning campaigns. In each of the five presidential contests dating back to 1992, Democrats have won at least 252 electoral votes.

"There's very little margin for error on the positive side for the Republicans," says Sandy Maisel, a political scientist at Colby College in Maine.

All of this represents a big change from a generation ago. GOP candidates won five of the six presidential contests from 1968 through 1988, twice carrying 49 states along the way. Pundits in those days spoke frequently of a Republican "lock" on the electoral college.

Democrats have since not just picked but blown apart that lock — despite the fact that much recent population growth has been in Republican red states such as Georgia and Texas.

They have managed to make