WILMINGTON, N.C. (AP) _ A Colombian senator with more than 20 years in office was convicted Thursday in U.S. District Court on 21 charges stemming from a cocaine trafficking operation.

Samuel Alberto Escruceria-Delgado, 52, could be sentenced to up to 270 years in prison and fined more than $4 million.

Escruceria-Delgado was convicted on 21 drug-related counts, including conspiracy to import cocaine, possession, distribution, interstate travel in aid to racketeering and aiding and abetting from May 1983 to October 1984.

Jurors were asked to decide whether he had headed an international drug smuggling crime family that supplied cocaine to a Wilmington drug ring or had been ensnared by lying drug smugglers who made deals with prosecutors to save their own necks.

''This case is a lawyer's nightmare,'' said defense counsel Jerrell Breslin in his closing arguments. ''You have an innocent man and three people who are lying.''

But Assistant U.S. Attorney Tom Swaim said evidence included immigration records that put the senator in Florida at the times alleged drug deals occurred.

Breslin argued that the government's entire case rested with the testimony of convicted drug dealers, and particularly with word of Jose Gutierrez, the man who headed a Wilmington drug network and identified the senator before a grand jury that indicted him in June.

Gutierrez pleaded guilty to a drug charge for which he could receive a 20- year prison term.

The senator's son, Samuel Alberto Escruceria-Manzi, a co-defendant the defense concedes was in the drug business, also is a Colombian congressman. He is in Colombia and has not been extradited.