The Diocese of Brooklyn's Bishop Nicholas DiMarzio is planning to take New York City Mayor Michael Bloomberg up on his offer to turn some Catholic schools into publicly funded charter schools. That would make Brooklyn the second diocese to take such a step, after the Archdiocese of Washington, D.C. The same move is under consideration in Chicago, according to the Chicago Tribune's Margaret Ramirez.Bishop DiMarzio disclosed his intentions toward the end of his column this weekend in the diocesan newspaper, The Tablet. He wrote: "Our working plan is to announce our intention to submit charter applications to the Chancellor for three schools in the coming weeks." Previously, the bishop had said he'd explore the mayor's offer.There are some serious legal obstacles, since the New York state law that permitted charter schools bars religious groups from running them, as the Gotham Gazette's Gail Robinson has written. But some legal experts believe there are ways around that.Bishop DiMarzio maintains in his column that it is possible to retain the Catholic character of these public charter schools and to make religious instruction available after school hours. If he goes forward with his working plan, some organizations will be eager to contest that.My question: What happens to the truly Catholic schools that have to compete with the tuition-free, quasi-Catholic charter schools? Won't this pose another threat to their existence?