DENVER - Colorado Democrats are planning sweeping changes to how elections are run in the state, to the dismay of Republican leaders who say they've been excluded from crafting a bill that that would allow same-day voter registration and require mailed ballots to every eligible voter.A bill of more than 100 pages is expected to be introduced this week, likely sparking a big partisan fight over whether the changes benefit one party over the other.Supporters of the changes, which also include eliminating the so-called "inactive voter" status, say the goal is to make voting more accessible."I think people are like me, they just want people engaged in the Democratic process," said Democratic Sen. Angela Giron, one of the bill sponsors. She insisted they didn't exclude Republicans from the process.Republican Secretary of State Scott Gessler, who oversees elections and has butted heads with Democrats on a range of issues, said the bill was "written in complete secrecy excluding anyone who may have a different point of view."Gessler said he first saw a draft of the bill Friday, and Republican Rep. Mark Waller, the House GOP leader, said Monday he had yet to see it."What's the motivation behind this? Well, it seems that's what the motivation is, to change the rules of the game in a very one-sided direction," Gessler said.Waller also said he's been left in the dark on the bill, despite his inquires."They've just kind of blown me off and gone on," he said.Under the bill, every registered voter in Colorado would get a ballot in the mail. They could still vote in person if they choose.Currently, Oregon and Washington mail ballots to every eligible voter, according to the National Conference of State Legislatures.In Colorado, 74 percent of voters cast a mail ballot in November, according to a letter to lawmakers from the state's County Clerks Association. In the letter late last year, clerks called that figure "a clear mandate from the electorate."The letter also said the label of inactive voters should be addressed.The bill eliminates the label for voters who failed to vote in the most recent election, which restricted their ability to get ballots by mail.Clerks also wanted to allow more time for people to register to vote and clear up confusion about different deadlines, but they did not specifically call for same-day voter registration.A draft of the bill, which is still being written, said the intent of same-day voter registration is "to remove barriers to participation and make voting and registration more convenient and accessible ..."Seventeen states have considered bills this year to allow same-day voter registration, including a proposal that passed in Utah, said Myrna Perez, an attorney with the Brennan Center for Justice. Perez said many states are introducing the bills in reaction to Republican-controlled legislatures that considered bills the previous two years that would require identification at the polls and reduced early voting.Giron said the proposed changes in Colorado were not meant to favor either party."I don't think it's a Democrat or Republican issue," Giron said. "I think Republicans want voters to vote, too."But some Republicans view the bill as Democratic strong-arming, now that Democrats control the Legislature after two years of split-party rule."It's just a continuation of the overreach that they've engaged in in this legislative session," Waller said.Last month, in what was one of the most intense debates of the session, Democrats used the power of their majority to pass new restrictions on firearms without a single Republican vote.State Republican Party Chairman Ryan Call said same-day voter registration, and mailing ballots to all eligible voters, could invite fraud."Democrats seem willing to trade election integrity in exchange for partisan advantage," he said.Supporters of the bill say the Republican concerns are unfounded, and that instances of voter fraud are extremely rare. They criticized Gessler for his comments."He's the one who's made it very partisan, by blowing it up before the bill is even introduced," said Ellen Dumm, a spokeswoman for Integrity & Modernization in Colorado Elections, a coalition of groups that have worked on the bill.