DENVER -- Election officials say an unchecked box on thousands of registration forms may keep many voters off registration rolls, but shouldn't keep them from voting.

"It means at this point in time they have an incomplete registration according to state law," said Adams County Clerk & Recorder Karen Long.

"They have the option of fixing the form before the election or casting a provisional ballot," Long said.

"On its face, it is confusing," said Secretary of State Mike Coffman. He blamed the confusion on competing philosophies in Congress.

"One said, 'You ought to have a photo ID card, a government issued ID card to vote or to register to vote.' The other side said, 'No you shouldn't.' So this is the compromise," Coffman said.

Voters who failed to check the box and don't have a government issued ID card can go back to the county clerk's office and correct it before Election Day.

Randy Hildreth, spokesman for the Colorado Republican Party said, "The state party doesn't really see it as a large issue. The secretary of state is providing a remedy."

Democrats are more concerned.

"I think it's important enough that if you disenfranchise any voter, there is something wrong with the system," said state Democratic Chairwoman Pat Waak. "We want everyone to have the right to vote, and the ability to vote."

In Denver, only a third of the problem has been corrected.

"We still have about 2,000 that will not be on the rolls unless they correct the problem before Election Day," said Michael Scarpello, the Denver Elections Director.

In Adams County, 695 voters forgot to check the box. Long is encouraging voters to fix the problem as soon as possible.

"They can go to early voting or they can come in on Election Day and remedy the situation," Long said. "But we really encourage them to fix it before they go and vote. It will make it a much cleaner and quicker process for them."

The Executive Director of the Colorado ACLU said she's concerned than not everyone whose forms are incomplete will know to ask for a provisional ballot.

Cathy Hazouri said she's also concerned that some provisional ballots won't be counted.

Coffman said letters are going out to everyone whose forms were incomplete. He said, "If they are legally entitled to vote, their provisional ballots will be counted."