Washington — Two United States journalists yesterday launched a legal battle that could affect the future of US aid to the ``contra'' rebels waging a guerrilla war against Nicaragua's Sandinista government. In a suit filed in federal court in Miami, the two charge that 30 Nicaraguan contras and American supporters engaged in a criminal conspiracy involving drug smuggling, gun running, attempted murder, and the bombing of a press conference in Nicaragua in which one of the plaintiffs was injured.
The plaintiffs say the conspiracy was intended to gain control of the military ``southern front'' in the contra war.
The suit claims that Adolfo Calero, the leader of the Nicaraguan Democratic Force, the largest of the contra groups, participated in a plot to kill Eden Pastora, the head of a dissident contra group then operating out of Costa Rica, Nicaragua's southern neighbor.
The case comes as Congress debates a Reagan administration proposal for $100 million in new, mostly military aid to the contras and as at least four congressional panels are inquiring into allegations of criminal activity by some contras.
``So far it's been all smoke and no fire,'' says one House of Representatives staff member of the charges being investigated. ``But if a `smoking gun' is found, in Congress or the courts, that could ice the issue of contra aid for good. At the very least, it should force the question of whether the US should use the contras as an instrument of US foreign policy.''
State Department and Justice Department officials say they have received no firm evidence backing up allegations of criminal wrongdoing authorized by contra leaders.
Mr. Pastora was severely injured when a concealed bomb exploded during a press conference just inside Nicaragua's southern border on May 30, 1984.
``It was a right-wing plot . . . to remove [Pastora] from being an obstacle to contra unity on the southern front,'' says Tony Avirgan, who was injured in the bomb blast. Mr. Avirgan and his wife and fellow journalist Martha Honey are plaintiffs in the Miami case.
The suit also ties several defendants to a plot to assassinate then-US Ambassador to Costa Rica Lewis Tambs. The complaint says the killing was to be blamed on the Sandinistas to generate more public and congressional support for the contras in the US.