St. Paul is where the first charter school — City Academy — opened in 1992 and where the charter school movement was born. Now more than 25 years later, there's an effort to put the brakes on growth of the popular public school programs.

That's because the Capitol City is now home to 35 charter schools, giving rise to discussions about competition for the taxpayer funds that support them and the governmental jurisdictions involved. The conversations raise the questions: Just how far can school choice go, and what controls can cities and districts place upon charters that, like all public schools, are created, funded and regulated by the state?

Those issues are being discussed now that the St. Paul teachers union and a community group, Parents for St. Paul Schools, have asked the City Council to consider placing a moratorium on charter programs. They want the city to do a study on the impact of charter schools on traditional public schools, the city's tax base and the community overall.

No proposed ordinance has been offered, although some council members have expressed interest in the idea.

The Star Tribune Editorial Board has generally opposed placing limits on the number of charter programs, in part because state legislators have over time and with our support imposed more rigorous criteria for creating the schools. As a result, Minnesota has about 164 charter programs, while some other states have several hundred. Of Minnesota's 860,000-plus public schoolkids, about 56,000 attend charters.

Charter schools were established to foster innovation that could ultimately improve all student instruction — whether it's delivered in traditional or independent charter programs. Now the schools have proliferated because of demand, giving students and families more options if they're unhappy with their traditional public schools. According to a Star Tribune news analysis, during the past 12 years charters have doubled their enrollments of St. Paul's school-age children from 11% of the population to 22%.

That trend has contributed to enrollment decline and less per-pupil state funding for traditional schools. Even after St. Paul voters approved $18.6 million a year in new funding last fall, school leaders are projecting a $2.9 million general fund deficit for 2019-20.

From the city's standpoint, one concern involves how charters can affect the property tax base. Charters lease or purchase buildings, and their nonprofit status makes them tax-exempt. One example cited by the city was a request from the Metro Deaf School to issue revenue bonds to finance the school's move to an Energy Park Drive building. That move would mean total taxes paid on the property would fall from about $250,000 to $36,000. As one council member noted, the city has a limited supply of vacant taxable property. And at least one school board member has questioned whether asking for more tax funding works at "cross purposes" when students and their funding are going to charters.

According to figures from the Minnesota Department of Education, 36 St. Paul charter locations receive state lease aid, and 15 sites have what are called "affiliated building" companies that can raise funding privately to own buildings.

Charter supporters argue that opponents want it both ways by asking voters to pay more and limiting competition. Charters do not receive any of the funds raised through voter-approved referendums.

Charters are an important part of Minnesota's education menu. They're growing because they offer something that families and students want. Perhaps that means there should be more cooperative arrangements between effective charters and traditional public schools to better serve students. But city and school officials should recognize that charters are here to stay.