PHOENIX—A bill aimed at blocking a move to allow unmarried domestic partners to get coverage as dependents under state employee and retiree benefits is dead in the water at the Arizona Legislature.

The state’s senate voted 16-14 against the bill after the sponsor switched her vote to position herself to ask for a future re-vote. It would define “dependent” as a spouse or unmarried child of an employee or retiree.

That’s counter to a rule change made by the Arizona Department of Administration and awaiting clearance from a state regulatory review council.

The change is supported by gay rights advocates and opposed by social conservatives.