TRENTON, N.J. – New Jersey’s Senate president is calling out the state’s teachers and police unions for an “extortion” scheme centered on a proposed constitutional amendment to guarantee billions of dollars flow into government worker pensions.

New Jersey Senate President Stephen Sweeney held a press conference today to call on the U.S. attorney and state attorney generals to investigate the New Jersey Education Association over alleged calls by union officials to Democratic Party chairmen in Bargen, Atlantic and Essex counties, NJ.com reports.

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A NJEA lobbyist reportedly threatened to withhold campaign contributions to Democratic candidates running for state office until Sweeney holds a vote on a constitutional amendment that would require the state to pour billions into public pensions.

“The constitutional amendment would require the state increase payments into the government worker pension fund. But Sweeney has so far declined to hold a vote on the referendum putting the amendment to the voters until lawmakers resolve a transportation funding impasse,” according to the news site.

Sweeney, a Democrat from Gloucester, told those at the news conference that the NJEA’s threats tied to the constitutional amendment, as well as a direct threat he received from Fraternal Order of Police President Bob Fox, constitute extortion and he’s written letters to U.S Attorney Paul J. Fishman and N.J. Attorney General Christopher S. Porrino asking them to investigate, PolitickerNJ.com reports.

“These unions are no longer engaging in public advocacy issues focused on education of our children,” Sweeney said. “Instead they have made specific threats regarding specific legislative actions that benefit the pocketbooks of its members. These unions have made it clear that unless they get their way, they will deliver on their threats.

“Using political and financial threats to coerce public officials is an assault on the integrity of the legislative process and honest government. And it could be illegal.”

The NJEA, the state’s most influential union, typically spends millions of dollars during the campaign season, nearly all of it going to Democrats.

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“The NJEA has specifically threatened to withhold political contributions unless – by next week – the State Senate posts and passes a proposed constitutional amendment to ramp up pension payments,” Sweeney wrote to Fishman and Porrino. “These threats clearly cross the line from lobbying to attempted bribery and conspiracy. Essentially, the NJEA has put members of the New Jersey State Senate in the position of tying specific official action to the receipt of a campaign contribution.”

According to Politicker NJ, “the letters shocked the New Jersey political world, who see Sweeney as one of the leading contenders in next year’s Democratic Primary for governor.

“Since his earliest efforts to overhaul the public pensions and benefits system, Sweeney has struggled to endear himself to public sector unions.”