Six U.S. embassy aides escape from Iran with Canadian help (Jan. 29). F.B.I.'s undercover operation “Abscam” (for Arab scam) implicates public officials (Feb. 2). U.S. breaks diplomatic ties with Iran (April 7). Eight U.S. servicemen are killed and five are injured as helicopter and cargo plane collide in abortive desert raid to rescue American hostages in Tehran (April 25). Supreme Court upholds limits on federal aid for abortions (June 30).Shah of Iran dies at 60 (July 27).Anastasio Somoza Debayle, ousted Nicaragua ruler, and two aides assassinated in Asunción, Paraguay capital (Sept. 17). Iraq troops hold 90 square miles of Iran after invasion; 8-year Iran-Iraq war begins (Sept. 19).Ronald Reagan elected president in Republican sweep (Nov. 4). Three U.S. nuns and lay worker found shot in El Salvador(Dec. 4).John Lennon of the Beatles shot dead in New York City (Dec. 8). Smallpox eradicated.