Two powerful unions donated a combined $3.6 million to New Jersey Gov. Phil Murphy's secretive "dark money" nonprofit, NorthJersey.com and the USA TODAY NETWORK New Jersey has found.

New Jersey's largest teachers' union, the New Jersey Education Association, wrote a $1 million check in April, a month after Murphy announced a 2019 budget the union called "progressive" and "people-focused." That donation is on top of the $2.5 million the union gave to the nonprofit in 2018, contributions reported by Politico.

And another union pitched in an additional $150,000 in June 2018, days before a budget deal was reached and a state shutdown averted: a local branch of the Service Employees International Union, 32BJ SEIU, which represents 12,000 property service workers in the state, such as office cleaners, security officers and food service employees.

When former aides to Murphy formed a nonprofit backing the governor's agenda, former campaign manager Brendan Gill said, "Transparency will be a key part of the agenda that we’re going to promote." The group called New Direction New Jersey — for which Murphy would solicit donations and also appear in commercials — would report who was giving it money.

The nonprofit reversed its pledge a year later, citing a "toxic political environment," and refused to name who bankrolled the nonprofit's push to pass Murphy's priorities, such as an increased tax on millionaires.

And a recent law intended to pull back the curtain on such political influence is now being challenged in court, and its future is uncertain.

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The public doesn't know much about New Direction New Jersey other than what reporters can piece together from public documents and press releases. Politico New Jersey found the first known donor in May, reporting that the NJEA contributed $2.5 million to Murphy’s nonprofit in 2018, after an adversary of the union found the information in NJEA meeting minutes.

NorthJersey.com and the USA TODAY NETWORK New Jersey identified a second donor and additional details about the leaders of the organization and what they are spending by looking through incorporation records and FCC filings.

It's unclear how much this $3.6 million in identifiable checks make up of what New Direction New Jersey raised.

See SEIU's donation and story continues below:

New Direction New Jersey hasn't yet filed any financial statements with the IRS that would show basic information about how much it raised and spent, what vendors it hired and what its top staff is paid. The governor has publicly asked the group to reveal its donors, but the nonprofit has not done as he suggested.

Uncovering these donations can be a sort of scavenger hunt. Take the NJEA donation: The union fully funds a political organization called Garden State Forward, which then donates to New Direction New Jersey. This information is included in federal IRS filings, not New Jersey campaign finance records.

Other public documents show some of the people involved in the operation who have not been highlighted in the press before: The group's president is Lisa Martinez, a former aide to U.S. Rep. Bill Pascrell Jr., D-Paterson, and its treasurer is Kathryn Weller Demming, a Montclair Democratic Committee member and former council member. Ethan Andersen is listed as a trustee. Andersen is the communications director for Princeton Strategic Communications and formerly was an advocate pushing for the passage of an assisted suicide bill, which went into effect this August.

Others associated with the group include former Murphy campaign manager Brendan Gill, former Murphy consultants Brad Lawrence and Steve DeMicco and the governor's campaign pollster, Danny Franklin.

New Direction New Jersey reported spending $1 million this summer on cable and digital ads during budget negotiations pushing for a millionaires tax, a policy that ultimately did not get passed. The group spent close to $65,000 on Facebook ads for New Jersey users, according to the Facebook political ad database.

The Federal Communications Commission requires reporting of ad contracts and schedules, but they are difficult to search. New Direction New Jersey submitted forms that show it spent close to $334,000 on ads during shows like the Trevor Noah "Daily Show," "Squawk Box," "Shark Tank" and "Morning Joe," according to data from the Center for Responsive Politics. The data shows hundreds of thousands of dollars spent on television ads in 2018 and 2019.

"Governor Murphy has proven himself to be a champion of middle-class workers and families, including our members," said NJEA spokesman Steve Baker. "After so many years of economic attacks on the middle class, and educators in particular, our members are proud to fight back under Governor Murphy’s leadership."

“32BJ SEIU supports organizations that champion working families by increasing the minimum wage to $15/hour, passing paid family leave and sick days for workers, and supporting the millionaires tax," the union said in a statement to NorthJersey.com. "32BJ backs a number of organizations and candidates that have a shared vision of fighting to bring working people into the middle class. Another part of this shared vision is fighting for fair and democratic elections where all working people have an equal voice."

"New Direction New Jersey is proud to have the support of groups like the NJEA and SEIU," said New Direction spokesman Philip Swibinski. "We support the progressive agenda being championed by Governor Murphy and his allies, and are working to make New Jersey stronger and fairer with advances like a $15 minimum wage, pre-K expansion, earned sick leave, equal pay, tuition-free community college and so much more."

Murphy is not the only prominent New Jersey politician with a closely linked "dark money" group. Senate President Stephen Sweeney, D-Gloucester, is supported by the General Growth Fund, a nonprofit that doesn't list its funders. And a group of political consultants recently formed a group to back Assembly Speaker Craig Coughlin, D-Middlesex, called NJ United. Its founders said it would disclose its donors by the end of the year, after New Jerseyans cast their votes in the Assembly elections.

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New Direction New Jersey's budget messaging struck a nerve with legislators, such as Coughlin, who urged the governor to intervene and stop the group's email blasts and ads attacking legislators for not supporting the tax increase.

"I have continued reading with dismay emails sent by New Direction New Jersey, an organization with which you are closely aligned,” Coughlin wrote in a letter to Murphy. “The rhetoric this group uses against fellow Democrats is beyond the pale — especially since the insults directed our way revolve around an area of disagreement over policy and do not merit the personal vitriol directed at members of my caucus."

And although Murphy signed a law that would require such 501(c)(4) social welfare nonprofits to reveal their formerly secret big-spending funders, the law is being challenged by a nonprofit founded by the megadonor brothers Charles and David Koch, Americans for Prosperity. The group says the law goes too far and will have a "chilling effect" on political speech. As the law was written, donors wouldn't be revealed to the public until early next year.

"Our organization will always abide by all state and federal laws, and we are in the process of reviewing legal challenges related to the state's new financial disclosure requirements for nonprofit advocacy organizations," said Swibinski, New Direction New Jersey's spokesman. "We will make any disclosure mandated by the new law when those challenges are decided, and we will be filing our annual 990 form with the IRS in November, as is required by law. We hope that all other advocacy organizations involved in the state will meet those requirements as well and be publicly held to the same standards."

The 990 form requires a group to list its big donors with the state, but that information is not available to the public.

If ultimately the "dark money" bill is ruled unconstitutional, voters may still have a chance to see the total picture of New Direction's funding. If Murphy runs for reelection, he is required to file detailed information to the New Jersey campaign finance authority about any nonprofit linked to him. But that won't be for years.