The Institute for Justice, a right-leaning legal organization, has filed a lawsuit against Douglas County Schools on behalf of three families who say a new school voucher program there discriminates because students can't attend private religious schools there using vouchers.

The lawsuit seeks to frame the case as a federal civil rights action:

"The exclusion of religious options from the program violates the Free Exercise, Establishment, Equal Protection, and Free Speech Clauses of the United States Constitution, as well as the Due Process Clause, which guarantees the fundamental right of parents to control and direct the education and upbringing of their children."

Douglas County’s original voucher program was open to faith-based schools. As CPR's Jenny Brundin reported last year:

The way the system was set up, families in the voucher program would get a check from the district to cover some or all of their private school tuition. They could only use that money at schools approved by the district. But -- and here's the heart of the legal case -- the program was wide open to religious schools. And that's where the vast majority of voucher students planned to go. Several groups sued the district, blocking the voucher program from going into effect. They argue it violates Colorado's constitution.

After the state Supreme Court ruled that approach was unconstitutional the district adjusted the program. In a statement Tuesday, district spokesman Paula Hans said:

“The Colorado Supreme Court ruled in its plurality opinion that if the district chose to run a grant program that included private schools it must exclude faith-based schools. While we disagree with that decision and have appealed it to the United States Supreme Court, DCSD still seeks to maximize the ability of families to match their students with the best educational environment to meet their unique needs."