Last week, the city filed the suit in Common Pleas Court. It asks for permission to unilaterally impose what Nutter says is the last offer to District Council 33, a union representing thousands of blue collar municipal workers.
On Tuesday, Nutter filed a petition with the Pennsylvania Supreme Court, asking it to take immediate jurisdiction. Three of the city's four biggest unions have been without contracts since 2009.
District Council 33 has rejected a city proposal that includes reduced pensions and furlough authority. The city says it needs to make changes to the pension system and health care.