In the debate about a state bailout for the Detroit school district, the greatest divide may be the future of charter schools in the city. Democratic lawmakers have often shown a bias against charter schools, and did so again this week.

Rep. Sarah Roberts, D-St. Clair Shores, proposed an amendment to a bailout bill (House Bill 5384) that may effectively ban new or expanded charter schools in the city of Detroit. A charter authorizer would be required to overcome a new layer of red tape.

Specifically, authorizers would have to get a determination by the state Superintendent of Public Instruction that a population of “underserved” schoolchildren lives within a 5-mile radius of a proposed charter school. The term is not defined in the bill, but if it is read to mean “within five miles of an existing public school” then few and perhaps no parts of the city would be open to new charters.

There are currently 65 charters operating in Detroit and 97 district schools.

The Roberts amendment was defeated in a party line 18-11 vote in the House Appropriations Committee. All 11 Democrats voting for the proposal and all 18 Republicans opposed it.

The House version of the bailout bill does not include a Detroit Education Commission, another device the Detroit political establishment could use to ration or ban new Detroit charter schools, which is contained in a Senate-passed bailout bill. For this reason, the current House bill is unlikely to get any Democratic votes.

The actual bailout provisions may be the least controversial part of the measures working their way through the House and Senate. There is a bipartisan consensus that the schools will be kept open, which means state debt relief will happen.

The committee vote is a clue, though, that Democrats will oppose any bill that does not hinder the charter school sector. What is unknown is how many Republicans will join them. If House Republican leaders are to pass a relief package without Democrats, only eight of the 63-member Republican majority can vote "no." In the committee vote to advance the Detroit school bailout package to the full House, three Republicans — Reps. Phil Potvin, Michael McCready and John Bizon — opposed the main bill of the package in committee.

Charters schools are currently the most accessible alternative for Detroit parents who do not want their children to attend a school run by Detroit Public Schools, which is deemed the worst urban school district in the country by the federal agency that produces biannual school report cards.

“More than half the parents in Detroit have made the choice to send their child to a charter school, and polls say that 75 percent of Detroiters say we need more charter schools in the city, not less,” said Michigan Association of Public School Academies President Dan Quisenberry. “Above all, charters are outperforming other public schools in Detroit by a significant margin. So any proposal to eliminate charter schools in the city is ludicrous, and it would obviously hurt students.”

The Roberts amendment’s unanimous Democratic support in the House committee further erodes the credibility of Democrats like Detroit Mayor Mike Duggan, who has said he wants a level playing field for all schools within his city. However, in 2014, Duggan approved a ban on selling city-owned property to charter schools located to close to a Detroit district school.

During a five-month period in 2014, Democrats in the Michigan Legislature introduced 10 bills and two budget amendments that would have imposed additional layers of oversight, new reporting requirements, regulations, restrictions, and in one case an outright ban on public charter schools.

The Roberts amendment again raises concerns about the fate of charter schools if Democratic politicians and others aligned with teachers unions and status quo DPS interests are given the power to halt new charters in the city and gradually squeeze out existing ones.

Charter schools in Michigan have outperformed traditional public school peers, according to Stanford University’s Center for Research on Education Outcomes (CREDO). In its 2015 report, CREDO found that students at charters in Detroit received the equivalent of a few weeks to as much as several months of additional learning in reading and math compared to their peers at conventional public schools. CREDO also said the city of Detroit should serve as a model for the rest of the country for how to operate charter schools.

Roberts didn’t respond to an email seeking comment.