The stage is being set Monday for something that hasn’t happened in New Jersey in more than two decades.

Members of the Democratic-controlled state Legislature, along with Republican support, are prepared to override Democratic Gov. Phil Murphy on a bill he conditionally vetoed that would force more political action organizations in the Garden State to disclose their donors.

A final decision to hold a veto override hasn’t yet been made and won’t be decided until Monday, multiple legislative sources told NJ Advance Media. But what’s clear if they go through with it is the powerful message members of Murphy’s own political party will send to the governor.

It would not only be the first override attempt in Murphy’s 18 months as governor. In fact, it would be the first time in more than 20 years that lawmakers overturned a governor’s veto.

The last time was in 1997, when then Republican-controlled Legislature reversed Republican Gov. Christie Todd Whitman’s veto of an abortion bill.

A successful override would be the latest sign of Murphy’s fractured relationship with key lawmakers as state budget negotiations heat up ahead of the July 1 deadline to have a signed deal to avoid a state government shutdown.

Democrats were mum late in the week on whether they were eager for an override.

But they have the votes.

Especially considering a top Republican lawmaker, state Assembly Minority Leader Jon Bramnick, R-Union, said in a statement Thursday there’s “overwhelming support” in his party “to override the governor’s ‘dark money’ veto.”

The bill has been kicking around Trenton for years. But it quickly landed on the floor of the Legislature for a vote in March because of a feud between Murphy and state Senate President Stephen Sweeney.

Sweeney, D-Gloucester, pushed for the legislation in an attempt to put pressure on a Murphy-aligned group — New Direction New Jersey — to disclose its donors after the organization broke its promise and did not name its backers.

The bill was also written in a way to take a swipe at Murphy political ally, his former campaign manager Brendan Gill, by barring elected officials from having any involvement in independent expenditure committees. Gill is an Essex County freeholder.

Murphy conditionally vetoed the bill in May and added his own jab at Sweeney in the process.

He added language that would require entities that receive more than $25,000 in tax credit subsidies from the state to be more transparent.

This was a swing at George Norcross III, the South Jersey powerbroker who’s Sweeney’s childhood friend and close political ally.

Murphy added the provision in the wake of news reports and findings from a special task force the governor set up to investigate how tax credits were doled out under former Gov. Chris Christie. Tens of millions of dollars in tax incentives had been awarded to companies and a non-profit associated with Norcross in Camden, where he is chairman of Conner Strong & Buckelew, an insurance brokerage, and chairman of Cooper Health System.

Lawmakers need a two-thirds majority to override a governor’s veto. That’s 27 votes in the Senate and 54 votes in the state Assembly.

The bill passed the Senate 33-0 and the Assembly 66-2 in March.

NOTE: An original version of this report incorrectly stated that former Gov. Christie Whitman had vetoed a bill that would have banned abortions after the first trimester of pregnancy. The bill dealt with a type of late-term abortion known to doctors as intact dilation and extraction but to abortion opponents as partial-birth abortion.

NJ Advance Media staff writer Brent Johnson contributed to this report.

Matt Arco may be reached at marco@njadvancemedia.com. Follow him on Twitter @MatthewArco or Facebook.

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