The subject Tuesday night is marijuana: how easy to grow, how profitable to sell, how severe the punishment if you are caught growing or selling or even just using. The producers of "Busted: America's War on Marijuana" (9 p.m., Ch. 7) take no position on the debate over the laws that have filled prisons with people who have committed a nonviolent crime, but they do clear the air a little.

This "Frontline" report begins in Indiana, in the heart of what is labeled "the marijuana basket of America," with the arrest of a suspected grower. Half of the marijuana used in the United States is domestically grown, and it serves quite a market; the program puts it between 10 million and 30 million Americans, more than those who use all other illegal drugs combined. With an ounce of marijuana going for more than an ounce of gold (now above $300) these days, it's quite a commodity.The program's experts distinguish marijuana from drugs like heroin and crack cocaine: it is less addictive, is not known for killing anyone, and at least one former drug agent notes that the people arrested for marijuana offenses do not strike him as a criminal element. But he adds that the serious charge against growers and sellers, which has brought very heavy federal sentences since 1986, is marijuana's reputation as "a threshold drug, the drug that most children start out with." Use of marijuana by youngsters has been increasing, their age decreasing.

Some users argue for their right to use and even grow the drug for reasons of health (voters in California and Arizona have passed laws more or less agreeing with them), religion or, as one activist puts it, the "right of consumption." But the argument is not so much about legalizing it as about making the punishment for marijuana offenses more flexible.

"Yes, I did break a law," says a man who was sentenced to five years for growing, "but I was no threat to the community or to my kids or to anybody else." The narrator explains: "Because mandatory minimum sentences do not allow parole, federal prisoners convicted on nonviolent marijuana charges sometimes serve more time than convicted murderers sentenced under state law."

Replying to proposals that sentencing should take into consideration the conduct of the people arrested, for example whether they are involved in violence or are promoting the drug among the young, hard-liners such as Sen. Orrin G. Hatch, the Utah Republican who heads the Senate Judiciary Committee and continues to support the mandatory sentences, says, "We ought to lock them up and throw away the keys."

Glimpsed in this many-sided report is a division in Americans' attitudes toward marijuana, evidenced by the contrast between the law's stern approach and the much lighter treatment in popular culture. Meanwhile, the famous war on marijuana goes on, costing the country at least $10 billion a year. Further inquiry is invited.