Gov. Christie says he has not decided whether to sign on to a 20-state lawsuit challenging the constitutionality of the health-care law signed in March by President Obama. That makes New Jersey one of seven Republican-led states that have not joined the largely partisan fight.

Interest groups on both sides of the debate are lobbying the governor, but some of his advisers say he should not join the suit. Capping property taxes and managing a difficult budget have rightly been his top priorities, they say, and New Jersey residents are more open than people in other parts of the country to health-care regulation.

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.

As he sees it, Christie has a choice: Pursue a lawsuit asserting states' rights or try to work within the law to get more of New Jersey's 1.3 million uninsured the coverage they need.

"I think he is sincerely exploring his options," Knowlton said. "He will land on the side of not pursuing the lawsuit."

A legal challenge would be politically unwise, said State Sen. Joseph Vitale (D., Middlesex), who has led state efforts toward universal coverage.

New Jersey is still a blue state, he said.

By joining the lawsuit, Christie "would ingratiate himself to the far right wing of his party, but they are in the minority in this state," Vitale said.

Christie is interested in "a New Jersey solution" that keeps as much of the health overhaul as possible under state control, spokesman Kevin Roberts said.

"When the governor has made up his mind on the lawsuit, he will make an announcement about it," Roberts said.

The state Department of Health and Human Services is expected to file a formal application next week for $141 million provided through the health-care law to cover the sickest people in New Jersey over three years.

With the state's application, the federal government would set up a high-risk insurance pool on the state's behalf.

When federal money became available to help close a gap in prescription coverage for seniors, Christie eliminated deductible and premium increases he had proposed in his budget.

"You can't have it both ways," State Sen. Raymond Lesniak (D., Union) said during a floor vote on a resolution he sponsored urging Christie not to join a legal challenge. "You can't be for the senior citizens and use the Obama health-care plan to fund their programs and then challenge it in court."

Rivkin said it was not unusual for states to challenge portions of a statute while taking steps to comply with it.

It happens often in relation to the Clean Air Act.

State Sen. Robert Singer (R., Ocean) spoke against the resolution, saying the new law did not address the issue of providing health care to illegal immigrants and put more financial strain on physicians.

In a later interview, he would not say what he believed Christie should do. But, he said, he wants the law thrown out. He would be happy if the lawsuit accomplished that.

The resolution passed, 21-16, and moved on to the Assembly.

State Sen. Joseph Pennacchio (R., Morris) called the resolution a waste of lawmakers' time.

That doesn't mean he wants Christie to take action.

He doesn't like the federal law, he said, but believes the state's fiscal problems are too immediate to spend time and money in court fighting it.

"I am personally glad and grateful that he is not being distracted by other things," Pennacchio said. "We can still reap the benefits [of a win] even if we don't" join.