The Denver suburbs in Jefferson and Arapahoe counties – which have been trending moderately Democratic in recent years – are where the swing voters live.
"That's where the battleground is," says Mr. Ciruli.
Colorado went for Barack Obama in 2008 by nine percentage points. Though it was considered solidly Republican before that, Colorado has been trending more liberal for years, and now has a Democratic governor and Democratic-controlled Senate. This year, the race is likely to be much closer, but Colorado seems to be trending slightly toward Mr. Obama. Though it has just nine electoral votes, it's a state that both Obama and Romney would like to win.
Obama, in fact, will be in the state just a week after Romney, visiting four Colorado cities in two days.
So far, Romney has focused his message in the state on his support for the hydrocarbon industry – and, of course, on the economy.
While Romney may have an edge with his economic message, political analysts say he needs to find a way to court the vote of suburban women – viewed as key by both camps.
"Obama will probably never win on the economy," says Ciruli, "but he can pick people off with narrowly focused issues, particularly for women. The Obama administration has rolled out an abortion issue here, and it raises a challenge [Romney] needs to be able to address."
Already, Obama's ads in the state (which he has also aired in other key swing states) angle hard for the women's vote.
One ad touts Obama's commitment to equal pay for women, and his signing of the Lilly Ledbetter Fair Pay Act. In another, Obama attacks Romney on his opposition to abortion rights.