DOVER, Del. — Gov. John Carney has vetoed a bill that would have prohibited Delaware charter schools from giving enrollment preferences to children living within a 5-mile radius.

Carney announced the veto Thursday, saying in a statement that he believes sponsors wanted to expand students’ options and boost diversity, but the bill “unfairly excludes some of our most vulnerable students.” He says it created a new standard that limits options for at-risk students in the Christina School District portion of Wilmington.

Critics say the geographic preference excludes minority and low-income students, while others say it helps maintain a neighborhood-school atmosphere. The bill applied to all charter schools but was aimed at Newark Charter, a predominantly white, high-performing school with a long waiting list of more than 3,000 students.