The moment Rep. Dan Pabon, D-Denver, received a letter from the Colorado County Clerks Association last year expressing the need to revamp the state’s elections system, it was music to his ears.

“They said what they wanted to work on, and they laid it out for us,” Pabon, who is the sponsor of an expansive piece of legislation that could change how Coloradans vote, told his House colleagues Thursday. “This (letter) was addressed to every senator and every representative in this body.”

Pabon’s comments sparked a marathon floor debate Thursday between Democrats and Republicans over a groundbreaking proposal that would send mail ballots to every eligible voter, allow Election Day registration and put all the counties on a real-time statewide database that supporters say would weed out those who try to vote twice.

The Voter Access and Modernized Elections Act was given initial approval by voice vote on Thursday night and is expected to be up for final approval Friday.

The proposal has been decried by state Republicans as a partisan effort by Democrats unwilling to reach across the aisle and work with them.

Several GOP lawmakers assailed Democrats, saying that because Republican Secretary of State Scott Gessler was excluded from helping draft the measure, it’s far from bipartisan.

“It’s disingenuous to call this bipartisan,” said House Minority Leader Mark Waller, R-Colorado Springs. “I saw this bill for the first time last week.”

Pabon noted that Colorado County Clerks consists of Republican and Democratic clerks from across the state.

Among the ins and outs of the measure is the requirement that county clerks and recorders set a minimum number of voter service and polling centers in districts.

“That’s not right, and it’s going to impact everyone regardless of party,” Waller said Thursday. “There’s a lot of people that still want to go vote at their local polling place.”

Democrats, who control both chambers and the governor’s office, struck down several amendments by Republicans, saying their concerns were already addressed in the 100-plus-page bill.

Rep. Carole Murray, R-Castle Rock, and several other GOP lawmakers said the far-reaching bill would, among other things, open up voter rolls to fraud.

“Same-day voter registration would do that,” said Murray, a former Douglas County clerk.

Murray added that Colorado was third in voter turnout in 2012, citing a George Mason University study. “Democrats are acting like Colorado is behind the curve in terms of our voter system, and that’s just not true.”

Murray stressed it would be impossible to implement these provisions before the November election — a sentiment shared by Gessler, who staunchly opposes the measure.

At its core, the Democratic effort would also get rid of the category of voter inactivity that is triggered when an individual fails to vote in an election and requires Gessler’s office to conduct a monthly national change-of-address search on all voters whose names appear in the statewide voter registration list.

Gessler has argued that testing the technology involved with some of these initiatives takes time and this measure is “flawed.”

“And it’s an example of bad government,” Gessler said at a House committee hearing earlier in the week.