TRENTON - New Jersey Democrats have returned from the presidential convention facing a deadline to pass a proposed constitutional amendment requiring the state make quarterly pension payments.

The proposal, which must be passed by the state Senate by Thursday to appear on November's ballot for New Jersey voters to consider, has stalled as legislators hash out how to pay for the state's road and bridge work.

The proposed amendment, backed by the Democratic-led Legislature, amounts to a promise to public-sector unions to ensure the state would meet its public pension obligations after Gov. Christie reneged on a 2011 law requiring specified payments.

The issue carries enormous political weight because the amendment is backed by the state's powerful unions, including the New Jersey Education Association, the state's largest teachers' union, and has been championed by Senate President Steve Sweeney, a possible candidate for governor in 2017.

Amid Bloody Mary-fueled breakfasts and the bustle of the convention floor, the issue percolated in the background at the hotel near the Philadelphia International Airport where New Jersey Democrats stayed during the convention. It was a top issue for NJEA president Wendell Steinhauer, who has lobbied lawmakers to pass the amendment, as he roamed the halls.

Senate Majority Leader Loretta Weinberg, an ally of Sweeney's, says the plan is for the Senate to pass the transportation-funding legislation Monday and the pension amendment at the chamber's next meeting Thursday. She acknowledged that failing to pass the amendment would be breaking a promise to public workers.

Republicans, including Christie, oppose the amendment and say requiring quarterly pension payments could require cuts to other programs.