And it led him to praise President Obama repeatedly on national TV, angering some Republicans who called it a betrayal.
"What a difference a couple of weeks can make," Lautenberg, 88, said in an interview. "This is no time for pitchforks. It's a time for shovels. I'm frankly pleased with the way he's handled this."
Christie, who has not said whether he will seek a second term next year, has battled Democrats in control of the legislature over spending and tax cuts. But he has pledged to avoid partisan politics during rebuilding and promised to seek federal assistance to defray the costs, for which he has said he does not yet have an estimate.
The governor may find Menendez and Lautenberg to be indispensable allies. The senators said last week that they had expedited $25 million in funding owed to NJ Transit, which suffered damage to 25 percent of its cars, had tracks washed out, and still faces ire from commuters as it attempts to cobble together rail service.
Menendez sits on the Finance Committee and chairs the banking subcommittee on housing, transportation, and community development, which he said would be important as New Jersey seeks to put displaced people into longer-term housing. Lautenberg is vice chairman of the appropriations subcommittee that oversees the Federal Emergency Management Agency.
"Even if Frank Lautenberg drives me crazy at times, which he does, it doesn't mean I don't understand his importance in the process of helping to rebuild my state and to aid the people who have been so severely damaged by this storm," Christie told reporters last week.
In March, Christie said Lautenberg was a "political hack" whose time had passed after the senator criticized his proposal to merge state universities. An "embarrassment to the state" was how the governor characterized him in April after Lautenberg grilled one of Christie's Republican appointees to the Port Authority of New York and New Jersey at a hearing in Washington.
The feud reaches back to Christie's 2010 decision to end an $8.7 billion project that would have built a new commuter-rail tunnel to Manhattan by 2018 to ease congestion as trains travel under the Hudson River. Lautenberg, an ardent backer, called the cancellation "one of the biggest policy blunders in New Jersey's history."
Sandy hobbled the state's mass-transit network after Amtrak was forced to close its flooded tunnel under the Hudson.
Menendez, 58, has served in the Senate since February 2006, when Jon S. Corzine, Christie's predecessor, appointed him to fill the seat left vacant when he was elected governor. At the time, Christie was U.S. attorney for New Jersey. When Menendez was locked in an election battle that year to retain his Senate seat, Christie's office subpoenaed records pertaining to a property Menendez rented to a Hudson County charity.
Still, they never had a personal quarrel like the one between the governor and Lautenberg, said lawyer Donald Scarinci of Allendale, a lifelong friend of Menendez's.
"To both of their credit, neither of them took a punch" in this year's election, Scarinci said.
Christie, who during the race called Kyrillos his best friend in Trenton, appeared at fund-raisers and campaign stops on behalf of him until Sandy curtailed the governor's stumping in the election's final stretch.
Before the election, Christie said he invited Menendez to tour damage with him and Obama, and again when they viewed storm-wracked Barnegat Bay by boat. A working relationship with Menendez is critical to navigate the state through its recovery, Christie said last week.
"We're going to need him to advocate for us in Washington, D.C., for the funding we're going to need to rebuild our state," Christie said.
On Nov. 4 in Hoboken, Menendez stood nearby and Lautenberg nodded in the front row as Christie gave a post-storm briefing. Homeland Security Secretary Janet Napolitano, whose department oversees FEMA, was there. Obama had flown over the state with Christie just days prior. That visit prompted Christie to praise the president's leadership days before the election.
"It's a change that is born out of necessity," said Krista Jenkins, director of the PublicMind polling institute at Fairleigh Dickinson University. "The last thing that public leaders want to do is communicate to voters that . . . at a time when we need them to work together and need state and federal cooperation, that they're at each other's throats."
The question, Jenkins said, is how long the truce will last. Given the political polarization in the country, the détente eventually will probably fall "by the wayside," she said.
Menendez said he has worked with Christie's administration before Sandy on transportation issues and in securing Medicaid provisions sought by the governor. He's "proud" of Christie's handling of the storm, even before it hit the coast, Menendez said.
"I don't live my life looking in a rearview mirror," he said in an interview. "We may differ on some policies, we have in the past and I'm sure we will in the future. But we're New Jerseyans first."