The state's largest teachers union is asking the Arizona Supreme Court to rule that recently enacted legislation affecting public school employees is unconstitutional.

A special-action lawsuit filed Monday by the Arizona Education Association challenges legislation dealing with such topics as teachers' seniority rights in layoffs and deadlines for school districts to decide whether to renew contracts.

The AEA contends the legislation approved last summer was illegal on several grounds. The union says it wasn't included as a topic for a special legislative session called on budget matters.

House Speaker Kirk Adams defends the legislation as valid. He says policy determinations are a long-standing part of budget-making.