Even by New Jersey standards, a news conference Gov. Philip D. Murphy held to announce that he was suing the Biden administration over New York’s plan to charge drivers to enter Midtown Manhattan was heavy on hyperbole.

A U.S. senator accused New York of orchestrating a “shakedown” of New Jersey commuters. A Democratic congressman implied that the fall from grace of New York’s former governor Andrew Cuomo was karmic payback for his support for the new tolls, known as congestion pricing. Another accused the head of North America’s largest mass transit system of giving children cancer.

“I feel like the Ginsu knife commercial,” Mr. Murphy, a Democrat, quipped — referring to a 1980s “wait, there’s more!” ad for a kitchen tool with many uses — as he added that New Jersey would pay a bonus to any state resident who worked remotely for a New York company and successfully sued to recoup out-of-state income taxes.

The gloves are off in a long-simmering border war between New York and New Jersey. And this latest battle has given rise to a curious new set of allies and enemies, allegations of hypocrisy and vivid trash talk — a situation that may grow only more intense as the start of congestion pricing nears, possibly in May next year.

Mr. Murphy, a self-proclaimed environmentalist with national ambitions, is trying to block a plan that seeks to address climate change. He is suing a transportation department controlled by President Biden, an ally, and headed by Pete Buttigieg, a once and future presidential contender.

New Jersey, a state run by Democrats, hired Randy Mastro — Rudy Giuliani’s chief of staff and deputy mayor when Mr. Giuliani was the Republican mayor of New York City — to file the lawsuit. Two days after Mr. Murphy’s announcement, Staten Island’s Republican borough president announced that he, too, would sue, praising Mr. Murphy’s leadership.

On the outside looking in are environmentalists furious at Mr. Murphy, whom they once regarded as a principled champion of policies to reduce carbon emissions that are rapidly warming the planet.

“Invest in transit, clean the air, show us that you really care,” a dozen protesters chanted outside Mr. Murphy’s announcement. They included some who have taken to dogging the governor at public events to highlight what they see as his failure to take necessary steps to meet his own ambitious goals for addressing climate change.

One demonstrator’s sign made her exasperation clear: “Gov. Murphy hypocrisy stinks.”

The new tolls, which could be as much as $23 at peak hours for vehicles traveling south of 60th Street in Manhattan, are intended to discourage driving and reduce emissions in one of the most polluted corners of the world.

Pricing details and discounts still must be worked out, but the tolls are expected to generate roughly $1 billion a year for capital improvements to keep the Metropolitan Transportation Authority’s buses and trains running efficiently — services many New Jersey commuters rely on.

“They’re benefiting from a better M.T.A.,” the authority’s chairman, Janno Lieber, said, pointing out that subway fares are subsidized by taxes that New Yorkers, not New Jerseyans, pay.

“Just to keep it in perspective, they do not pay for the subsidies that go to the subways,” he added.

More than three in four New Jersey residents who commute to work in New York already take mass transit, according to an analysis by the Tri-State Transportation Campaign. The average income of the roughly 39,000 residents who drive is $108,000, compared with $88,000 for public transit users, according to the study and transit officials.

If successful, the congestion fee is expected to reduce Midtown traffic by about 20 percent, or roughly 143,000 vehicles.

Similar congestion-pricing systems exist in London, Singapore and Stockholm. But New York’s would be the first of its kind in the United States. M.T.A. officials said they regularly fielded calls from leaders of other big cities and even small tourist destinations who are watching New York’s rollout with interest.

“Our hope is that, when we get this accomplished, it will encourage other jurisdictions,” Mr. Lieber said.

Not if New Jersey can help it.

Representative Josh Gottheimer, a Democrat, has for years been one of New Jersey’s leading opponents of congestion pricing. He has in past arguments depicted New York as trying to balance its budget on the backs of New Jersey drivers and focused on traffic models that show the tolls could mean slightly more car and truck traffic in his Bergen County district.

Drivers of some vehicles are likely to alter their routes to avoid paying the congestion fee when entering Lower Manhattan through the Lincoln or Holland Tunnels. These so-called toll shoppers might instead use the George Washington Bridge, north of the congestion zone, leading to what an environmental analysis estimated would be a 1 percent increase in harmful emissions near Fort Lee, N.J.

But on July 21, the day New Jersey filed its lawsuit, Mr. Gottheimer — the congressman who accused Mr. Lieber of giving children cancer by increasing car emissions near the George Washington Bridge — lingered on a newer point.

More cars, he said, would be bad because of the pollution they generate. But, he noted, fewer cars would also be bad, leaving the Port Authority of New York and New Jersey with less money because of a reduction in toll revenue for the agency, which operates the main crossings between New York and New Jersey.

“It will also cost the Port Authority nearly $1 billion in investment for capital projects over the next decade,” Mr. Gottheimer said.

“If you screw with Jersey, buckle up,” he added. “We’re not backing down.”

Political tension between the states is hardly new.

A quarter-century ago, New York and New Jersey squared off over ownership rights to Ellis Island. In 2010, former Gov. Chris Christie of New Jersey pulled funding at the last minute from a critical Hudson River tunnel project now known as Gateway, sidelining the effort for years. This spring, New Jersey won its legal battle to withdraw from a partnership set up 70 years ago to keep organized crime out of one the nation’s biggest cargo ports.

Mr. Murphy had already made a personal appeal to Mr. Biden to block congestion pricing. His decision to escalate the argument by filing a federal lawsuit also provided another benefit: a well-timed opportunity to change the subject from a blizzard of unpleasant transportation news at home.

Local news headlines have warned that New Jersey Transit, the state’s beleaguered bus and train system, is on track to have a $917 million deficit by the time Mr. Murphy leaves office in 2025, notwithstanding his oft-repeated promise to “fix New Jersey Transit, if it kills me.”

Fare hikes, layoffs and service cuts are suddenly on the table, and the transit agency’s pricey lease for its new headquarters in Newark is facing scrutiny, three months ahead of key legislative races. Republicans are calling for hearings.

New Jersey’s congestion pricing lawsuit argues that the environmental assessment conducted by the M.T.A., which ran nearly 4,000 pages, was insufficient; the federal government, according to the lawsuit, has shirked its responsibility by failing to require a more thorough study, which would probably take years.

Mr. Buttigieg, who in 2020 competed for the Democratic presidential nomination and was later named to Mr. Biden’s cabinet, declined through a spokesman to comment.

But the lawsuit’s prime argument rang hollow to New Jersey environmentalists, who have called for a similarly thorough environmental review as they fight Mr. Murphy’s plan to add as many as four lanes to a highway that leads into the Holland Tunnel, which is not getting wider.

The project, expected to cost a stunning $10.7 billion, will be funded by New Jersey Turnpike tolls — money opponents argue would be far better spent improving the state’s mass transit system.

“It’s clear that the governor’s administration is prioritizing the needs of drivers,” said Yonah Freemark, a transportation and land-use researcher at the Urban Institute, a nonprofit based in Washington. “It is very difficult for someone who is against congestion pricing and who is promoting an enormous highway widening to take the mantle of being pro-environment.”

Interviews with New Jersey officials about the lawsuit suggest that they hope to exact pricing concessions for drivers or a share in the toll windfall, in addition to pushing back the 2024 start date.

“Without a seat at the table, we were left with no choice but to file a lawsuit,” Mr. Murphy wrote in a letter submitted to The New York Times.

Mr. Lieber said he had a hard time understanding the justification for New Jersey’s claim that it deserved a piece of the revenue pie, pointing to the tolls that New York drivers regularly pay when they drive on the two main highways that cut through New Jersey.

“They’re literally doing exactly the same thing with their tolling that they are saying is evil in our case when we do it,” Mr. Lieber said.

“It smells like a double standard.”