A bill that would require school districts to share local tax overrides with their charter schools was passed 22-13 by the state Senate Tuesday, a key step for the controversial measure.

As amended, Senate Bill 16-188 would phase in revenue sharing over two years, rather than requiring full sharing beginning in 2017-18.

Senators voted 25-10 to pass a companion measure, Senate Bill 16-187, which contains other provisions sought by charters and also was amended significantly.

The two bills have sparked a sharp rhetorical tussle between charter advocates and district supporters during full debate on Monday. Differences focused on each side’s perceptions of “funding equity” versus “local control.”

While supporters argued that charters need financial equity, opponents said charters actually have an edge because many have waivers from various state education laws, including the requirement to hire licensed teachers.

“This bill ensures all of our children are worth the same amount,” said sponsor Sen. Owen Hill, R-Colorado Springs, during final debate Tuesday.

During preliminary debate Monday Hill argued that charters on average receive 80 percent of the per-pupil funding given to neighborhood schools, Hill said, “The bill works to ensure our constitutional requirement for a thorough and uniform public education system does apply to all schools.”

“Every school board in this state has the opportunity to sit down and negotiate with its charters. That is the way I think it should be,” said Sen. Rollie Heath, D-Boulder. “I think this bill fundamentally destroys that balance.”

At issue is the additional local revenue many districts raise on top of the basic support provided by the state school finance formula. Those revenues, called mill levy overrides, can be used for general operating expenses or for specific programs, depending on the ballot measure language approved by voters. Of the state’s 178 districts, 118 have overrides of different types and raise a combined $860 million a year.

Only about three-dozen districts have both override revenues and charter schools. The amount of money in dispute is not large. The Colorado League of Charter Schools, a major backer of the bills, estimates more than 60 percent of override revenues already are shared with charters and that only $20-$25 million isn’t shared. There is wide variation in the percentage of money individual districts share.

But it’s the principle of the thing for both sides, and the two measures are the most contested education bills of the 2016 session.

The amendments didn’t necessarily reassure bill opponents.

“They helped, but we really have to talk about it,” said Jane Urschel, deputy executive director of the Colorado Association of School Boards. “Our folks will still have their concerns.”

The Senate amendments, engineered by Hill and Sen. Mike Johnston, D-Denver, were clearly intended to read a compromise and improve the bills’ chances.

One important change involved the state Charter School Institute, which supervises a group of charters that aren’t connected to districts. The original version of SB 16-188 proposed creation of a system for providing extra state money to charters equivalent to what they would receive from overrides if they were chartered by districts. That section was removed.

A Johnston amendment also trimmed SB 16-187. Its remaining provisions allow top-rated charters to file improvement plans every two years instead of annually, streamlines audit requirements and requires districts to notify their charters when vacant buildings or land may be available.

Removed were provisions that would have required more detailed accounting of the services districts provide to charters and that would have made it harder for districts to regain exclusive chartering authority, which limits the role of institute within a district’s borders.

The amended bill also eliminates the ability of charters to get automatic waivers from the state requirement for a minimum number of teacher-student contact hours.

A proposal that particularly irritated school districts, allowing applicants for new schools to appeal to the state if they felt districts weren’t negotiating in good father, was included in a draft version of the bill but was discarded before introduction.

The final votes on the two bills cut across partisan and geographical lines.

All 18 Republicans and seven Democrats voted for HB 16-187. Democratic support slipped for HB 16-188, with only five Democrats voting for the bill. One Republican voted against it.

The four Democratic senators who represent areas of Denver, which has the state’s largest concentration of charters, were split on the bills. Johnston and Irene Aguilar voted for both while Lucia Guzman and Pat Steadman voted against both.

See roll calls for SB 16-187 and SB 16-188.

Two other charter bills are pending in the session’s final days. House Bill 16-1343 would reduce many of the waivers from state law that charters currently receive automatically. Senate Bill 16-209 would stabilize funding from schools that move from district control to institute oversight, and vice versa.