While candidates cram in final campaign appearances and pitches this weekend, for the battleground state of Colorado, Election Day really began more than two weeks ago. Almost 1 million or 55 percent of expected votes have been cast, according to Colorado Secretary of State Bernie Buescher's office.

The majority of the state's active voters are permanent mail-in voters, meaning they automatically receive absentee ballots for all elections. As of late last week, the GOP was ahead of the pack: 41 percent of Republicans had cast early ballots by mail and in person, compared to 35 percent of Democrats. The holy grail of Colorado politics, unaffiliated voters, have been holding tight to their ballots the longest, with just 23 percent making up their minds. This gets attention because these independents make up a big chunk of the electorate here and they truly swing races.

Security is serious. The mail ballot process verifies signatures. Bipartisan teams of judges compare ballots to signatures on file, to prevent fraud. Once early and mail ballots are submitted to a county clerk's office, they are processed and scanned, but the vote tabulation isn't released until Tuesday night. Voters can track their ballot status. The "already voted" are public record, allowing organizers to narrow their final get-out-the vote efforts.

Secretary Buescher says feedback is mixed. Voters like the convenience and extra time to mull their choices, but "...campaigns hate them, because it lengthens the time they've got to do their work." Ken Buck, the Republican in the money saturated, neck and neck race for Colorado's U.S. Senate seat, echoes that challenge, "...we have done our best to really get our message out early, to get our get out the vote effort early, and to stay energized for three weeks. It's much more difficult than the days when you could aim at November 2nd and spend all your resources on that day."

A press release from the National Association of Secretaries of State notes that thirty states, plus the District of Columbia, permit absentee voting by mail, without having to provide a reason and 34 states have an early in-person voting period. Two states, Washington and Oregon have all mail ballots.