It wasn't an angry outburst, but state Senate President Stephen Sweeney's message was sent.

At a mayor's conference in Trenton on Thursday, Sweeney publicly bristled at Gov. Phil Murphy for calling on state lawmakers to pass legislation designed to combat President Donald Trump's gutting of New Jersey's property tax deductions. Sweeney suggested that if the governor wants something from lawmakers, "he should just call us rather than call us out publicly."

Then Sweeney, D-Gloucester, said Murphy's biggest item on his wish list -- a millionaires tax -- is now "absolutely a last resort."

It's no secret the relationship between Trenton's top two Democrats has been frosty during Murphy's first month in office -- something that could hamper the governor and his ambitious agenda. Insiders say Murphy and Sweeney rarely talk directly to one another.

And those who worry about worst-case scenarios have seen this picture before.

The last time Democrats controlled every branch of state government, a fight between a rookie governor with Goldman Sachs ties (Jon Corzine) and a south Jersey legislative leader (Joe Roberts, the state Assembly speaker) produced an epic week-long state shutdown that made last year's version look like ... well, a day at the beach.

But just one month into Murphy's tenure, nobody is predicting all-out war -- especially since the governor and Democratic lawmakers are itching for change on so many issues after eight years of Republican Gov. Chris Christie.

"I think everybody on all sides of the fence here are busy getting their sea legs," said state Senate Majority Leader Loretta Weinberg, D-Bergen. "I think a lot of it has been over-hyped."

"Are there some bumps in the road? Sure," Weinberg added. "Communication between the legislative leadership and the administration, I think can be improved."

Assemblyman Ralph Caputo, D-Essex, said everything now is just "new" and "everybody has to adjust."

"Hopefully it'll settle down and we'll be able to work together," Caputo said. "I think (Murphy and Sweeney) will get to trust each other more. No matter what the perception is, they're gonna have to work together."

Weinberg said Murphy and the Democratic-controlled state Senate and Assembly are "kind of in agreement on practically all of these big issues."

But two of Murphy's biggest campaign promises -- passing a recreational marijuana law that could generate hundreds of millions in tax revenue and increasing taxes on millionaires -- have received pushback from fellow Democrats.

If Murphy is stripped of his revenue raisers, he'll be unable to fund any number of things on his long list of campaign promises, from fully funding schools and the state's ailing public worker pension fund, to raising the minimum wage and making community college free to New Jerseyans. When combined, those promises will cost the state billions of dollars.

At the same time, some lawmakers have privately expressed frustration with how Murphy has spent much of his first few weeks signing executive orders, largely overturning Christie policies or fighting Trump. Some believe the approach is ironically reminiscent of Trump.

Instead, they say, Murphy could be working with the Legislature to pass his initiatives into law. Eight years ago, rookie leaders Christie and Sweeney forged an early bond and teamed up on big-ticket items, such as property tax caps and pension reform.

Matthew Hale, a political science professor at Seton Hall University, said the first month of Murphy's tenure has been akin to watching a "listening tour."

"The governor has been going around and listening and doing some low-hanging fruit," Hale said. "All of the big-ticket items that we may have expected haven't been done yet."

Hale said right now, Sweeney and Murphy "seem like fighters throwing out jabs."

"No one's ready to throw a punch hard," Hale said. "They're sort of testing each other, finding out their boundaries."

Brigid Harrison, a political science professor at Montclair State University, stressed: "The reality is: The governor needs the Legislature. Even Chris Christie recognized that."

The bad blood between Murphy and Sweeney goes back to early in the campaign season.

Sweeney eyed a gubernatorial run before he was pushed out by Murphy. The New Jersey Education Association opposed Sweeney's reelection and Murphy, who was endorsed by the union, declined to pick a side.

Some wonder if the tension between the two men will affect Murphy's first state budget, which he's expected to unveil on March 13.

One source said they could see a scenario in which Murphy includes the millionaires tax in the budget, which Sweeney would oppose, and that could set the stage for a lengthy battle over how to fund the state. The source did not want to publicly discuss sensitive matters and asked for anonymity.

Republicans, meanwhile, hint at something else.

Assembly Minority Leader Jon Bramnick, R-Union, said there's a new dynamic at play. When Democrats controlled the Legislature under Christie, they could pass bills that Christie would never sign and "play to a constituency without worrying about the impact of bad policy" because it would never become law.

"Now the Democrats have to govern," Bramnick said. "Some of those policies they voted for in the past, it's harder to vote for now. It's pretty well known in politics that campaigning is a lot easier than governing."

For his part, Murphy has said repeatedly that concern over his relationship with Sweeney is overblown. Speaking after a news conference in Marlboro on Friday, the governor said his team is "talking to (Sweeney's) team every day."

When asked about Sweeney's comments the day before, Murphy said the Senate president has shown he's on board with the tax plan to allow people to deduct property taxes as charity.

"The most important thing Sen. Sweeney said yesterday -- which I think was great -- was that we're all together on this," Murphy said.

Sweeney told NJ Advance Media that Murphy is "working hard" early in his term.

"He's busy getting a handle on what's going on," Sweeney said.

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

Brent Johnson may be reached at bjohnson@njadvancemedia.com. Follow him on Twitter @johnsb01.