NEW YORK – Charter school supporters worry that if Democrat Bill de Blasio becomes the next mayor of New York City, as expected, it will have a chilling effect on the alternative public schools – or worse.

De Blasio, who currently leads his Republican challenger Joe Lhota by roughly 40 points in the polls, is on record as saying the city doesn’t need any more charter schools – despite the 53,000 students who are languishing on charter school waiting lists.

The mayoral frontrunner also wants to end the practice of allowing charters to locate in public school buildings that have extra space. It’s a concept known as “co-location,” and de Blasio has proposed putting the practice on ice, according to New York Daily News columnist Errol Louis.

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Even more worrisome to charter advocates, de Blasio wants current “co-location” schools to start paying rent to their public school “landlords.” Earlier this year, he said allowing charter schools rent-free access to government-owned buildings is adding “an insult to injury.”

If de Blasio succeeds in his anti-charter plans, it will starve existing charters of financial resources and make it nearly impossible for new schools to open in the high-rent city, Louis writes.

Why is de Blasio so eager to make life difficult for the city’s 183 charter schools, which, by most accounts, have done an admirable job educating some 70,000 students?

An amNewYork editorial offers an answer: “We only see one real reason to do this – and that’s to make the United Federation of Teachers happy. The (teachers) union has never liked the idea of charters, whose teachers do not necessarily have to abide by UFT rules. The more that charters succeed – and they’re a major hit – the more the UFT seems to worry.”