Karen Franklin, Ph.D.

In February of last year, 39-year-old Billy Jack Gaither of Sylacauga, Ala., was brutally beaten with an ax handle. His throat was slashed and then his body was set on fire.

In Wyoming, six months earlier, college student Matthew Shepard was tortured and left for dead. In Kentucky, Pfc. Barry Winchell was bludgeoned to death by another soldier while Winchell lay sleeping. In Redding, Calif., Gary Matson and Scott Mowder were shot to death in their bed.

These cases are some of the most shocking results of homophobia, the hatred or fear of gay people. But as this week's new "Frontline" documentary makes all too clear, they're not isolated incidents. In fact, the FBI reports that bias crimes against gays doubled between 1990 and 1998.

So much for modern-day tolerance.

In "Assault on Gay America" (9 tonight, PBS/Channel 8) "Frontline" producer Pryor Malis and correspondent Forrest Sawyer use the Gaither murder as a springboard from which to explore the nature of homophobia in our country, both as a catalyst for hate crimes and as an attitude that permeates society. It's an unnerving and painful - but significant - hour of television.

The program points out that while a majority of Americans have come to believe homosexuals deserve the same rights as heterosexual citizens, almost half of them believe that homosexuality is a sin or just plain wrong.

The chilling byproduct of this attitude is that some feel they're entitled - even expected - to punish others for their nonconforming sexual preferences.

Dr. Karen Franklin, a forensic psychologist who appears in the program, has produced the only scientific study of perpetrators of anti-gay crimes. She tells "Frontline" of one offender who insists that if a man doesn't "carry himself in a masculine way, he's looking to get beaten up, and it's perfectly acceptable to beat him up."

As usual, "Frontline" does a solid job of engaging various sources, including a teen in Reno, Nev., who dropped out of school because of ongoing harassment; the Rev. Jerry Falwell, who, while clinging to his belief that homosexuality is a sin, admits the anti-gay rhetoric may have gone too far; and Henry Adams, a University of Georgia professor, whose surprising results of a 1996 test demonstrated that for some, anger against gays may derive from fears of one's own homosexual desires.

The real heart of the hour, however, belongs to Billy Jack Gaither, who struggled to live discreetly in a backwater town that hardly embraced the homosexual lifestyle. Absorbing interviews are conducted with family and friends, as well as the two men who murdered Gaither.

In the latter conversations, all the hatred and corrosive ignorance, along with that twisted sense of entitlement, are plainly evident.

"He (Gaither) asked me to let him go and told me he wouldn't say anything," one of the killers recalls. "I told him it was too late. . . . "