PROVIDENCE, R.I. (AP) — Rhode Island’s Supreme Court has dealt a legal setback to Providence in disputes with retired city workers that could prove costly.

The court ruled Tuesday that the city violated the U.S. and state constitutions in 2012 when it suspended cost-of-living adjustments on retiree pensions for an indefinite amount of time.

The biggest decision found that if the pension plan for city employees and retirees is changed by the courts, it can’t be changed again by the City Council, unless the workers agree.

That means the city’s 2012 pension reform does not apply to several dozen retired firefighters and police officers.