Differing views of the legislature’s powers over labor and contracts law were at the center of oral arguments Tuesday in a lawsuit that challenges one part of Colorado’s landmark 2010 teacher evaluation law.

“The Colorado legislature has plenary power to modify these teacher employment rights,” lawyer Eric Hall, representing the Denver Public Schools, argued to a three-judge panel of the Colorado Court of Appeals.

But Philip Hostak, a National Education Association lawyer from Washington, D.C., countered, “plainly there are” limits on legislative power to change contract law.

The two were pitching their arguments in the case of Masters v. DPS, filed in January 2014 by five former teachers and the Denver Classroom Teachers Association. The suit claimed district officials misused the mutual-consent provision of the evaluation law, violating both contract and due process sections of the Colorado Constitution.

One part of the evaluation law, known as Senate Bill 10-191, requires mutual consent of a teacher and principal for assignment of a teacher to a school. Before the law was passed, non-probationary teachers would be assigned to a school solely by decision of district administration.

Under SB 10-191, teachers who aren’t placed go on a district waiting list and ultimately lost employment rights if not placed within a certain period of time.

Denver District Judge Michael Martinez dismissed the plaintiffs’ claims – and the case – in June 2014, prompting the union to take the case to the Court of Appeals last December.

On legislative power, while Hall stressed the General Assembly’s powers, Hostak argued there are limits on the legislature’s power to impair contracts.

The two also offered different interpretations of a 1991 bill that changed teacher employment law and removed the word “tenure” from those laws. Removal of the word was unimportant, Hostak argued, rhetorically asking the law changed a non-probationary teacher’s property right. “The answer to that is a resounding no.”

But Hall argued the 1991 law “got rid of any idea of tenure.”

The lawyers also had different views on the effect of SB 10-191’s mutual consent provision. Hall argued that “displacement and dismissal are two different things.” Given the legislature’s constitutional duty to supervise schools, changing mutual consent “is entirely consistent with the legislature’s power.”

But, Hostak maintained, “the end result is the same” and teachers are deprived of due process rights.

The DCTA is asking the appeals panel to send the case back to district court for trial. Whatever the panel rules, that decision likely will be appealed to the Colorado Supreme Court.

The CEA fought hard against the new evaluation law during the 2010 legislative session, but the mutual consent provision is the only part of the law being challenged in court. The law’s major provisions – requiring annual evaluations, basing half of annual evaluations in students’ academic growth and loss of non-probationary status for teachers rated partially effective or ineffective for two consecutive years – are being implemented in all state school districts.

Tuesday’s hearing marks the second DCTA-DPS conflict in the Court of Appeals this summer. In June a different three-judge panel ruled that the district violated the 2008 Innovation Schools Act by not getting staff consent for creation of some innovation schools in 2011 and 2012 (see story).