Granting driver's licenses to undocumented immigrants is a hot-button issue that Democratic Assembly Speaker Craig Coughlin, is determined to say nothing about until after the November elections.

Fellow Democrat Phil Murphy, a staunch supporter of the idea, operates by his own political calendar.

The unapologetic liberal governor wants a stalled bill legalizing licenses for potentially 460,000 undocumented immigrants on his desk for his signature as soon as possible, even if that it means having voters badger Assembly candidates in the final four weeks of the campaign.

"It's a no-brainer,'' Murphy told a crowd inside Temple Ner Tamid in Bloomfield on Monday night. "I'm frustrated that it's not on my desk. I encourage you to call your Assembly person, your senator, and ask him why it is stuck and not on the governor's desk, because I will sign it."

Murphy's lobbying — and Coughlin's furious response behind closed doors — illustrates the divide in the state Democratic Party, which has led to gridlock on key issues like legalizing marijuana, health benefits reform and raising the income tax.

Coughlin, a low-key lawyer from Woodbridge, is a pragmatist who hews to the play-it-safe playbook. As leader of the campaign to retain and possibly expand the party's 54-26 majority in the Assembly this fall, he is eager to avoid hot-potato topics that could give Republicans an advantage in a handful of tossup districts.

Preserve the votes before spending political capital on risky legislation, the theory goes. That requires steering the party along a more centrist path, like walking away from Murphy's plan to raise taxes on millionaires.

It also means keeping your heads down when Murphy vows to turn New Jersey into a "sanctuary state,'' as he did during his 2017 campaign. Coughlin did join Latino activists last January in support of driver's license legislation, but he has kept it on the back burner and out of view until after November.

Coughlin declined to comment Wednesday.

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Murphy, who has little support from a Legislature dominated by his own party, has largely ignored the traditional rules and rhythms of "inside the bubble" Statehouse politics.

He has positioned himself as something of a liberal "outsider" battling the entrenched, boss-dominated forces that resisted progressive change. It's a strategy that has left him with few friends in the Legislature but fairly popular with voters.

And he draws his support from a coalition of public employee unions and array of grassroots progressives who are more inclined to clash with party leadership than to bow to their marching orders.

But for the moment, Coughlin's fears appeared justified. The speaker reportedly went ballistic after hearing Murphy's remarks in Bloomfield, according to two sources, angry at Murphy for needlessly injecting a sensitive issue that could put vulnerable Democrats on the defensive. And, as if on cue, Republicans seemed to prove his point.

Republican candidates in the 16th Legislative District, a likely battleground that stretches from Princeton through Somerset and into parts of Middlesex County, called on Assembly incumbents Andrew Zwicker, D-Princeton, and Roy Frieman, D-Hillsborough, to sign a pledge never to vote on the bill.

"Only in Phil Murphy’s New Jersey could you require legal citizens to provide six points of identification to get a driver license, and then turn around and give one to someone who cannot produce a single piece of identification that says they are even an American citizen,” said Mark Caliguire, a Republican challenger from Montgomery.

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Murphy's remarks also reinforced suspicions that he really doesn't want Assembly Democrats to expand their majorities, fearing that it will only make it harder for him to advance his agenda in the Legislature. Call it passive-aggressive sabotage.

Murphy allies say the reaction is overblown and that the governor has repeatedly called on the Legislature to pass the immigrant driver's license bill over the past year. They cite a survey, commissioned last year by Let's Drive NJ Campaign, that said 54 percent of voters support driver's licenses for the undocumented, while 29 percent opposed it, with 17 percent saying they were unsure.

Dan Bryan, a Murphy spokesman, defended the governor's remarks.

“He has always been honest and straightforward with the people of New Jersey, and that is something he won’t apologize for," Bryan said. "He looks forward to working with legislative leadership to bring this measure forward.”

At Tuesday's event, Murphy argued that opposition to giving undocumented people driver's licenses was rooted in resentment, that granting them a benefit would somehow diminish the rights of legal U.S. citizens.

"This is the 'us versus them' world we live in right now,'' Murphy said.

The same thing could be said about the divided Democratic Party he now leads.