A Hartford Superior Court judge will hear oral arguments Friday on motion to dismiss a lawsuit disputing the constitutionality of the state budget—the same day unions are expected to officially reject the labor agreement the budget is contingent upon.

The lawsuit, filed by two Republican lawmakers, two former lawmakers, and a conservative think tank called the Roger Sherman Liberty Center, claims that the budget signed by Gov. Dannel P. Malloy violates a constitutional provision requiring the state’s expenditures to match its revenues. The budget was signed with a $2 billion placeholder set aside in the bill for union concessions.

Last month the governor announced a plan to fill a $400 million gap in the budget, obtained largely with unanticipated increased revenues, but the remaining $1.6 billion was expected to come from the savings and concessions included in the tentative labor agreement.

Tomorrow marks the end of a several week-long union voting process and the votes counted so far have left little possibility the unions will approve the agreement. Malloy acknowledged that fact in a Thursday statement calling for a special legislative session to close the budget deficit.

“It was always my hope that the SEBAC Agreement would be ratified and we could move forward with the process of getting our state’s fiscal house in order and creating new jobs,” he said. “But that looks increasingly unlikely.”

Roger Sherman Liberty Center Board Chairman Jack Fowler said Thursday the seemingly imminent failure of the labor agreement only adds credence to the argument that the budget was unconstitutional.

“I think the wheels coming off the union bus here makes our case that much stronger,” he said. “The fact that it’s based on the whims of a union vote shows it’s not in line with the constitution.”

Earlier this month, the state filed a motion to dismiss the lawsuit, asserting that it would be improper for the court to get involved with an ongoing process traditionally left to the legislature and the governor.

“Once the budget process is complete, the plaintiffs’ claims will likely be moot, rendering adjudication at this time even more wasteful and imprudent,” the motion read.

The hearing is scheduled for 10 a.m.