With 16 of 23 states led by GOP governors fighting the new law, at least one national expert said Christie faced the risk of becoming an "outlier through inaction."
"He's going to have to explain why he has stood out among his colleagues in his own party by not doing something they've all done," said Michael Franc, vice president for government relations at the Heritage Foundation, a conservative policy group in Washington.
Whether he signs on or not, Christie's background as a prosecutor means his choice will be "highly regarded," Franc said.
The new law mandates that all U.S. citizens and legal residents have health-care coverage starting in 2014 or face penalties. Proponents say the mandate is necessary to control insurance premiums and spread the cost of covering everyone.
Top officials from 20 states have challenged the requirement in a U.S. District Court in Florida, calling it "an unprecedented encroachment on the liberty of individuals." Among them is Pennsylvania Attorney General Tom Corbett, the Republican nominee for governor. Virginia has filed its own suit.
It would be a "good thing" to have New Jersey aboard, said David Rivkin, lead outside counsel representing the 20 state plaintiffs.
"As a matter of law, it does not matter how many states you have," he said. "As a matter of symbolism and gravitas, it's quite important."
It's too late for Christie to automatically join that group. A judge would have to allow the state to become an intervenor.
David Knowlton, president of the New Jersey Health Care Quality Institute and chairman of the governor's transition committee on health care, said Christie should not make that request. And he does not believe the governor will.