The Unification Church's brass band had just launched the first bars of "We Shall Overcome" into the icy wind outside the Russell Senate Office Building yesterday morning when Sen. Bob Dole (R-Kan.) banged his gavel to quiet the animated audience packed into the Senate's largest hearing room.

The hearing, and the public relations battle that enveloped it, had begun.

To the members of the Rev. Sun Myung Moon's Unification Church, the roles in yesterday's congressional hearing on "The Cult Phenomenon" were clear. The "Moonies" were the early Christians, and Bob Dole was Caligula. It was the old battle between belief and persecution, the church members said; only the tactics were new.

"This is a struggle over the content of tonight's network news," explained Niel Salonen, president of the U.S. branch of Moon's church. "When Dole held his hearing on us three years ago, we got kicked in the gut on national TV. We had to mobilize today or else there was going to be another slash on the nightly news."

To the deprogrammers and other anticultists -- whose fervor seemed at least equal to that of the sects they testified about -- the hearing was a chance to spread their warning that the growth of cults is a threat to traditional American values.

"Cults are proliferating," said Rabbi Maurice Davis of White Plains, N.Y., a Moon critic whose testimony was punctuated by shouts of anger and hatred from the audience, "and we had better remember that... the path of the cults leads to Jonestown."

The only persons at yesterday's session who seemed unclear about its purpose were Dole and the eight other members of Congress who attended, with obvious discomfort, the animated hearing.

Last fall, in the wake of mass deaths in Guyana and a House subcommittee report on Moon's ties with the Korean Central Intelligence Agency, the South Korean spy agency, a hearing on the Unification Church and other "new religions," as Dole called them, seemed like a good idea.

Yesterday as they listened to Salonen and leaders of some traditional religious organizations denounce the hearing as an invasion of religious liberty, Dole and his colleagues seemed to be having second thoughts.

"We have no intention of interfering with religious freedom," the Kansan said. "But we have constitutents... There is interest in these matters."

Dole annnounced in an opening statement that the session was "not a media event," but he was wrong. The hearing, and the Moon followers' demonstration outside, were thick with camera crews and reporters, as Salonen had known they would be.

The Unification Church had made a deliberate tactical decision, Salonen said, about the hearing. Much of the session dealt with sects in general rather than Moonies in particular; the Moon group, by appearing en masse, necessarily focused attention on itself.

"We knew that would happen, yes," Saloen said, "but we figured they would feature us anyway. And when Sen. Dole knew we were coming, he canceled a witness, a crazy woman who was going to say we have a suicide ritual. Just for that not to make the network news tonight was worth the whole effort."

About 60 Moon followers found seats in the hearing room, and more thn 300 others waited outside beneath a huge paper banner ("Repeal First Amendment! Dole for President") that billowed and finally ripped in the frigid breeze.

They were not the only protesters on Capitol Hill yesterday, and inevitably the twain met. The church members' hymns were drowned out by the tractor caravans but there were no hard feelings. Church women passed out cookies to farmers entering the Russell building to lobby for higher price supports, and the farmers were a patient audience for the Moon followers' sermons about their "New Kingdom."