Colorado public schools are a step closer to a major funding overhaul after Gov. John Hickenlooper signed a new school finance act that proponents say would provide a long-overdue modernization of an antiquated school funding formula for classrooms across the state.

But the governor’s signature May 21 doesn’t make the reform measure a done deal.

Voters must give the go-ahead to the legislation’s price tag of about $1 billion in new taxes, something Republican lawmakers are sure to rally against in the fall. If a vote falls short this November, the proposal could come back for funding votes through 2017.

Hickenlooper, who was flanked at the Capitol bill-signing by legislative co-sponsors of Senate Bill 213, dubbed the “Future School Finance Act,” hailed the legislation as a way to “allow Colorado to vault to the top of every state” when it comes to school financing and transparency.

“This bill really positions Colorado to be the national leader in terms of school reform, in terms of school effectiveness,” Hickenlooper said.

The legislation would mark the most sweeping change to the state’s school finance formula that’s been seen in decades.

The act would fund full-day kindergarten, provide preschool for at-risk children and would increase needs-based programs for special education students and children who are learning English.

The legislation also would provide more funding for students who are involved in gifted and talented school programs.

The bill would give school districts greater flexibility in being allowed the opportunity to have longer school years and school days, if they choose to do so.

The bill also is expected to increase per-pupil funding for most school districts across the state by way of a funding system that supporters say is a more equitable way of divvying up money.

Under the new formula, the state would determine how much revenue individual school districts are able to raise, with the state backfilling the difference.

The state also would provide more support for local mill levy-matching. And, the bill would create a new teacher evaluation formula that supporters say is badly needed.

Sen. Mike Johnston, D-Denver, was the main driver behind the legislative effort. The former Thornton High School principal said the bill marks a “tremendous step forward” in making Colorado a school reform model for the nation.

“Instead of forcing (students and teachers) to work in a system that was created before the Internet, email and cell phones ... they instead will work in a system that is built for the 21st century,” Johnston said.

But Johnston’s efforts could be all for naught if voters do not approve funding, which would come in the form of some sort of tax increase. Rep. Millie Hamner, D-Dillon, a bill sponsor, acknowledged that “the biggest challenge” will be in convincing voters to provide funding for the measure.

Backers of the act don’t yet know what the tax measure will look like on the fall ballot.

Hickenlooper would not say which tax measure he preferred, but did say that he “certainly” will campaign for the effort.

Republicans denounced the reform measure as a bloated effort that would lead to greater bureaucracy and doesn’t do enough to put in place necessary school reform measures.

They also say the bill is nothing more than a $1 billion tax increase on the people of Colorado.

The new school finance model would not take effect until the 2015-2016 school year. The 2013-2014 school funding model came in a separate piece of legislation.