TRENTON — Lawyers for the state argued in a brief filed Thursday that the court can not dictate how large a pension contribution Gov. Chris Christie recommends in his state budget proposal.

Responding to a lawsuit filed by public employee unions over a $1.3 billion pension payment included in the budget for the fiscal year beginning July 1, the state said Christie's $33.8 billion spending plan was merely a first draft for the Legislature to consider, amend and ultimately adopt.

Christie's recommendation is less than half of what is required under a 2011 law, and the unions contend Christie has breached their contractual right to a $3.07 billion pension payment in the next fiscal year.

The unions had also asked the courts to intervene in the current budget year, and Superior Court Judge Mary Jacobson decided in February that workers were entitled to the full payment that Christie slashed to balance the budget.

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The state Supreme Court has agreed to hear the administration's appeal to this ruling next month.

In March, the state troopers union filed a brief saying that Jacobson's ruling for this year's payment should compel Christie in future years, and without it, public workers "continue to suffer irreparable harm."

The governor's proposed payment "deliberately evades the mandates of the (full pension payment) and intentionally underfunds the state's obligation in an attempt to run out the clock," the troopers' brief said.

The state responded Thursday that the unions are rehashing a legal argument the court rejected last summer that "the governor's recommendation, in and of itself, does not present a legal question fit for review until the Legislature acts, because the governor's spending recommendation itself has no force of law and therefore has not impaired the contractual rights of plaintiffs or violated separation of powers principles."

Even if Jacobson's ruling that workers have a contractual right to the payments under the 2011 law holds, that doesn't extend to the governor's proposal, the state Attorney General's Office argued.

"The public interest is best served by allowing the two branches constitutionally charged with fiscal responsibilities to play out their roles in the FY16 budget process without judicial interference," the brief said.

In addition, the Attorney General's Office said the lower contributions were not causing immediate harm, because the pension fund was still able to pay retirees' benefits.

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Samantha Marcus may be reached at smarcus@njadvancemedia.com . Follow her on Twitter @samanthamarcus. Find NJ.com Politics on Facebook.