Nicholas Palen Thimmesch, 57, a nationally syndicated newspaper columnist who was a resident journalist at the American Enterprise Institute for Public Policy Research, died July 11 at his home in Chevy Chase. He had liver cancer.

Mr. Thimmesch, who wrote for the Los Angeles Times Syndicate, had been a syndicated columnist since 1969. He had previously been Washington bureau chief for Newsday and a reporter for Time magazine, the Des Moines Register and the Davenport (Iowa) Times.

He had been with American Enterprise Institute since 1981, working on a project on "Communications in a Free Society" while continuing to write his column. In recent years he had organized and moderated seminars and symposiums on such issues as media coverage of the Reagan administration, economics, wars, the Middle East and the attitude of media elite.

Mr. Thimmesch was the author of several books, including "Robert Kennedy at 40," "The Bobby Kennedy Nobody Knows," and "The Condition of Republicanism." He edited a volumn drawn from one of his seminars, "Aliteracy: People Who Can Read but Won't," and he wrote essays for such publications as Sports Illustrated, The New York Times Magazine, Esquire, Life, Cosmopolitan and McCall's. He was a frequent guest on radio and television programs, including "Meet the Press" and "Face the Nation."

He was born in Dubuque, Iowa, served 22 months in the Merchant Marine in the late 1940s and graduated from the State University of Iowa, where he taught for two years before entering journalism.

Mr. Thimmesch was a member of the H.L. Mencken Society and in 1974 served on the President's Commission on the World Population Year. He was a fellow at Harvard's John F. Kennedy School of Government in 1980-81. He had been a resident of the Washington area for the last 19 years.

Mr. Thimmesch's marriage to Susan Winora Thimmesch ended in divorce. Survivors include two daughters, Elizabeth Trafford of London, and Martha Thimmesch of Los Angeles, and three sons, Nicholas P. II, Peter and Michael, all of Chevy Chase.