DENVER -- While the Ds and Rs battle over whose candidate is best suited for the White House, the Us rule Colorado.

Unaffiliated. Undecided. Undeniably in control.

The time left to reach those crucial voters is running out.

"I really like McCain, John McCain. And Obama impresses me, I mean as being fair and honest. And I like that," said Michael Ball, an unincorporated Adams County resident. "I'll decide here probably in the next few days."

An Obama volunteer knocked on Ball's door Monday, one of several face to face meetings on Louise Drive.

Dan Subry estimates he's knocked on at least 600 doors in recent weeks.

"There's been some that've been out and out rude, but most people are pretty good. I think Americans are pretty good people, really," Subry said.

Both parties are using sophisticated computer models to pinpoint exactly which homes on a given street have swayable voters.

"Absolutely they should expect to get knocks on the door between now and election day," said Tom Kise, communications director the the McCain campaign.

Right now, Republicans think Mesa, Weld, Larimer, El Paso, Arapahoe, Adams and Douglas counties have desired, unaffiliated voters to target.

"I'm sure they'll be contacted on one way, shape or form before it's all said and done," Kise said.

In Arapahoe County, 32 percent of the registered voter totals are unaffiliated with more than 48,000 requesting mail-in ballots, which could already be filled out and on the way.

"Nobody's knocking on the door but I've been getting a lot of phone calls. I've decided not to answer the phone. I'm trying to make my own decision," said undecided voter Brian Exley.

The gap of Democrats over Republicans has widened too, according to Arapahoe County Clerk and Recorder Nancy Doty, to roughly 4,000.

Both parties said they should know within two days once a mail-in ballot is received, so they can remove that voter from their list of all-important undecideds.

Clerks from Jefferson, Adams and Douglas counties said thousands of mail-in ballots from unaffiliated voters have already arrived, with Douglas County putting the number at 50 and 60 percent.