Harvard Law School officials yesterday cancelled a speech at the Law School by former contra leader Adolfo Calero after a protester not affiliated with the University tried to attack the speaker.

As Calero stepped forward to deliver his speech, Joshua Laub, a Tufts senior, rushed to the front of the room and leapt onto the podium. Harvard University police pulled Laub, screaming epithets, to the ground and handcuffed him after a brief struggle.

Laub--who is charged with three criminal violations--identified himself as a member of the International Committee Against Racism (INCAR), a Marxist student coalition. He is free on $15 bail and will be arraigned Monday.

The speech, which was originally scheduled to be held in Austin Hall's Ames Courtroom, was delayed by a half-hour after Law School officials received a telephoned bomb threat. Police decided to move the audience of about 350 to Langdell Hall.

While police and members of the Law School Republican Club--which sponsored the speech--carefully searched bags and coats and checked identification cards at the entrance to Austin, members of the club said that security was not as tight at Langdell.

However, at least 15 Harvard police officers and two plainclothes officers filming events were present at both locations. Law school officials and members of the Law School Republican Club said Laub may have entered the heavily guarded event using a forged Crimson press pass.

In addition to the tight security, Law School Republican Club officials said they distributed all but 300 of the 350 available tickets to Law School conservative students and conserva- tive organizations at other schools, includingboth UMass campuses, the Massachusetts Instituteof Technology, Bradford, Merrimack, Brandeis,Boston College. Tufts and Wellesley.

About 20 members of La Alianza, an organizationof Latino Law School students, who obtainedtickets had planned a peaceful protest inside thehall with the permission of Law School Dean ofStudents Sarah Wald. Had the speech proceeded, thestudents were permitted to hold placards and standwith their backs towards Calero.

Before the speech began, Assistant Dean forInternational and Comparative Legal StudiesFrederick E. Snyder said any interruption of thespeaker would threaten Calero's First Amendementrights and bring the speech to an end.

Law School Republican Club President JosephAnderson said Calero wanted to return to thepodium after Laub's arrest, but that Harvard LawSchool officials had decided to close down thespeech.

"We were vetoed," Anderson said, saying thatLaw School officials cancelled the speechunnecessarily. "Dr. Calero wanted to proceed, andit was not his decision to close the thing down,"he said, calling Calero courageous. "He's onetough hombre," Anderson added.

Anderson said that he did not know whetherCalero, who made a special trip to appear atHarvard, would return to Cambridge. The third-yearlaw student said that he did not know whetherproper security provisions could be made to allowthe contra leader to speak.

Protesters, administrators, and the event'sorganizers said they wished that Calero had beenallowed to speak after Laub was dragged from thehall.

"I very much regret that Dr. Calero was notable to make his statement," said Law School DeanJames Vorenburg, who attended the event."Particularly in a university setting, we all havea great interest in freedom of speech."

James Vigil, Jr., a second-year law student whohelped organize the protest, said, "I don't thinkanybody supported what he did."