Republican Gov. Bruce Rauner on Friday referred a contract dispute with the largest state employee union to a state labor panel whose members he appoints.

If the Illinois Labor Relations Board determines the two sides have reached impasse, that sets up the possibility of a worker strike.

Rauner and the American Federation of State, County and Municipal Employees Local 31 have been at odds over a new contract to replace the one that expired June 30. The two sides had been negotiating for months under an agreement that neither would initiate a work stoppage without first taking the matter to the labor board.

Rauner took that step Friday when he asked the board to decide whether or not the state and union are at impasse — a legal term that, if reached, would allow Rauner to try to impose his own terms without a contract deal in place. The union could resist those changes by going on strike.

Both sides contend that the other has refused to continue to negotiate.

The administration said in a news release that the union had “refused to seriously negotiate for the 24th bargaining session in a row on any of the core contract proposals presented” by the governor’s negotiators.

The labor board is a panel of people appointed by the governor. AFSCME has indicated that it might turn to the courts in order to force Rauner back to the negotiating table.