BOSTON – As many on the right lament America’s litigious culture, a conservative senior citizens group has, with little fanfare, filed a far-reaching federal lawsuit that could cost the tobacco industry more than $120 billion.

The Virginia-based group, United Seniors Association, signed onto the suit last year after the American Association of Retired Persons rebuffed an offer to serve as plaintiff in the case, one of the lawyers involved said yesterday.

The lawsuit, filed in federal court in Boston, charges that the major cigarette manufacturers deceived smokers about the addictive powers of nicotine and therefore should be liable for the federally funded Medicare program’s expenditures on smoking-related illness.

“One of the issues we’re very concerned about is where corporations are involved in misconduct that forces the taxpayer to become an insurer,” the chairman of United Seniors, Charles Jarvis, told The New York Sun. “In this case, what you have is a decades-long purposeful suppression, and that is the fact about nicotine being not only psychologically addictive, but physically addictive.”

An attorney for United Seniors, Robert Cynkar, said the lawsuit aims to recover about $60 billion in smoking related claims Medicare has paid out since 1999. Under the “private attorney general” provision United Seniors is using to bring the case on behalf of the government, the tobacco firms would have to pay double damages, with half going to the treasury and half to United Seniors.

Mr. Jarvis has said that if the full $120 billion is recovered, United Seniors would turn over more than 99% of the money to the treasury.

Tort reform advocates said they were startled that an organization billed as a conservative alternative to the AARP would back a massive suit against the tobacco industry.

“This is frivolous,” a resident fellow with the American Enterprise Institute, Theodore Frank, said. “I really don’t know what is in United Seniors’ heads in doing the trial lawyers’ bidding like this.”

A scholar at the Manhattan Institute, Walter Olson, said the suit puts United Seniors in the same camp with perennial litigants against the business community such as New York’s attorney general, Eliot Spitzer.

“I don’t think the overwhelming majority of the conservative movement knows this group is out on this particular frolic and detour,” Mr. Olson said. “It announces a retroactive and radical theory that tobacco sellers were certainly not informed of at the time.”

Messrs. Frank and Olson noted that the federal government brought a similar claim in its long-running lawsuit against the tobacco firms, but a federal judge in Washington, Gladys Kessler, dismissed that part of the case in 2002.

Mr. Cynkar said that ruling is no longer relevant because in 2003 Congress passed legislation clarifying the provision that is the basis for the United Seniors’ lawsuit, the Medicare-as-second-payer statute. That law requires the federal government be reimbursed when private insurance companies have liability for an injury that causes a Medicare claim. The 2003 amendment, proposed by Senator Grassley, a Republican of Iowa, made clear that the provision applies both to insurers and to companies that self-insure, such as the tobacco firms.

Last month, Mr. Grassley filed an amicus brief supporting the legal theory under which United Seniors brought the case. However, the senator’s brief said he was not taking a position on whether the tobacco companies should ultimately be held liable.

“As long as the courts keep misreading congressional intent in the statutes, Senator Grassley is going to try to set them straight,” an attorney for the senator, Brian Koukoutchos, said in an e-mail to the Sun yesterday. “There is no reason why a company that chooses not to buy a liability policy and instead chooses to self-insure should be allowed to shove the costs of its negligence onto the American taxpayer.”

Asked about conservatives who warn of the menace of litigation, Mr. Cynkar said, “I’m one of those conservatives you are talking about.” The Republican lawyer also said he worked as an aide to Edwin Meese, an attorney general under President Reagan.

“Here, people were not given their choice” to smoke, Mr. Cynkar said. “The marketplace can only work if you have accurate information out there.”

On its website, United Seniors, which also calls itself USA Next, purports to back tort reform, particularly in the area of medical malpractice. “USA Next leads the fight to fix our badly broken litigation system. AARP stands in the way,” the site says.

“Our involvement in a taxpayer protection suit like this regarding the tobacco industry is completely consistent with our concern about frivolous lawsuits,” Mr. Jarvis said yesterday.

United Seniors was founded in 1991 by a conservative direct-mail fundraiser, Richard Viguerie. However, in recent years the organization has received the bulk of its funds from a few donors, such as the pharmaceutical industry. The seniors group has run television advertising campaigns in favor of the Medicare prescription drug plan and President Bush’s efforts to create private Social Security accounts.

Mr. Frank, the tort reform advocate, said United Seniors’ support for the anti-tobacco litigation would probably come as a shock to pharmaceutical companies, which have provided the bulk of the organization’s budget in recent years. “United Seniors is adopting a legal argument that could essentially destroy the pharmaceutical industry,” he said.

Mr. Jarvis, a former legislative director for Mr. Grassley, said the situation involving the allegedly deliberate fraud by the tobacco industry was unique and had no implications for other manufacturers. “There are really no parallels in any other area that really apply,” he said.

The tobacco firms have moved to dismiss the lawsuit. A judge is expected to hear arguments on the motion in May.