For a low-budget, made-for-TV thriller, "Last Best Chance" has a high-brow pedigree.

Former Sen. Fred Thompson, now of "Law and Order" fame, stars as the president of the U.S. The plot has a Tom Clancy feel, with al Qaeda terrorists stealing enough nuclear materials to incinerate London, New York and Washington. The film also has the backing of Ted Turner, former Georgia Sen. Sam Nunn, Tom Brokaw, the heads of the 9/11 Commission and Warren Buffett, who at last weekend's Berkshire Hathaway Inc. annual meeting urged his 20,000 shareholders to order it.

Still, nuclear Armageddon isn't an easy sell.

The movie was the brainchild of Mr. Nunn, who has spent years pushing to keep nuclear arms from falling into the wrong hands. Even in the wake of the Sept. 11, 2001, terror attacks, he feared the government was moving too slowly to address the threat while the public was largely inured to it.

So Mr. Nunn, who isn't known for his left-coast sensibilities, decided to go Hollywood. He persuaded the bipartisan board of his advocacy group, the Nuclear Threat Initiative -- which he co-heads with Mr. Turner -- to spend $1 million on a made-for-TV movie dramatizing the clear and present danger of nuclear terrorism.

"We had to find a way to communicate the threat," Mr. Nunn says.

Mr. Nunn acknowledges that the movie was a "high risk" venture, especially with money tight at the NTI since the value of Mr. Turner's original pledge to the group of five million Time Warner Inc. shares shrank in value after the company's merger with America Online went south.

Whether a TV thriller can rally the nation to action against nuclear proliferation isn't clear. In fact, it isn't even clear that the film will ever make it to the small screen. One cable-network executive who has seen it found the language "kind of stilted," adding that "if we went with it, we'd want changes."

The 45-minute film starts with Russian mobsters trying to bribe a Russian Army guard to steal two small tactical nuclear warheads for their al Qaeda clients. The guard balks, and winds up dead in the trunk of a car. But the terrorists have other options.

An al Qaeda special-operations team steals highly enriched uranium fuel rods from a research reactor in Belarus while a South African scientist easily walks out of his nuclear research lab with a lead-lined bag filled with thin sheets of weapons-grade uranium. "I keep the books," he explains later when asked by his co-conspirators if the uranium will ever be missed.

What the terrorists manage to do next is even more chilling. Working in low-tech machine shops they turn their stolen uranium into three "gun type" nuclear weapons, similar to the one dropped on Hiroshima in 1945. "It's not true that the designs are on the Internet ... . But a reasonably smart person with ... maybe a master's in physics" and several months to spend in a library could figure it out, says Matthew Bunn, who heads Harvard University's "Managing the Atom" project and was the technical adviser for the movie.

The rest of the film's action focuses on the frantic and increasingly futile efforts of the Americans and Russians to find the weapons before they go off.

For a movie about the risks of nuclear annihilation, it's noticeably lacking in cool special effects. The film's writer and director, Ben Goddard, best known for the "Harry and Louise" commercials attacking the Clinton health-care plan, says his $1 million budget "wouldn't have paid for a fraction" of what was needed to plausibly blow up Washington or New York. Besides, both he and Mr. Nunn wanted to leave the audience with some sense of hope.

The film is the latest public-education effort by Mr. Nunn's group. In 2003, the NTI spent $1.5 million on issue ads for the Iowa caucus and New Hampshire primary that created a local buzz and whetted the group's appetite for a national audience. The rest of the time, the NTI tries to plug some of the holes in nonproliferation policy.

Three years ago, the group spent $5 million to help remove 100 pounds of weapons-grade uranium from a poorly guarded nuclear-research reactor in Serbia. The Serbs wouldn't let go of the fresh uranium -- enough for about two nuclear weapons -- unless they got help cleaning up their highly radioactive spent fuel, something the U.S. government wouldn't pay for.

Mr. Turner is so passionate about the nuclear threat that he keeps a small, typed card in his wallet bearing both his important phone numbers and the text of the disarmament section of the Nuclear Nonproliferation Treaty. In a rare moment of self-effacement, he says that when he first got involved in big-time philanthropy, pledging $1 billion to the United Nations in 1997, he never considered trying to do anything about weapons of mass destruction. "I thought it would be presumptuous for a private individual," or even a nongovernmental organization to take that on, he says. But "when I got into it I found ... that governments were just letting it slip."

When Mr. Turner made his original pledge to set up the NTI, the stock was valued at $250 million, but ended up being worth only $70 million -- all of which has been spent. Mr. Buffett, who says he has worried about nuclear annihilation since Hiroshima, stepped in to bail out the group. He has donated $5 million a year for the past two years and has raised his contributions to $7 million a year through 2009.

As a sweetener for potential distributors, "Last Best Chance" comes with 15 minutes of Mr. Brokaw, the former NBC anchor, interviewing Mr. Nunn and Republican Sen. Richard Lugar, the godfathers of the Nunn-Lugar effort to lock up loose Russian nukes. Mr. Nunn also has persuaded some key members of the 9/11 Commission to go on the road to lead postfilm discussions.

The best marketing muscle, for now at least, may come from Mr. Buffett's plug to his shareholders. While explaining why Berkshire's insurance units exclude nuclear, chemical and biological attacks from their policies -- "We would regard ourselves vulnerable to extinction if we didn't" -- he urged them to order the film online from www.lastbestchance.org. In a telephone interview, Mr. Buffett says he has used past annual meetings to recommend books, and "they've shot way up on Amazon."

The NTI has ordered 20,000 DVDs of the film it plans to give away to people who request one on the Web site, which it scrambled to put up in time for Mr. Buffett's meeting. By late Monday afternoon, it had received 3,945 requests. The DVDs are expected to be available by midmonth.