Robert S. Allen, 80, one of Washington's most colorful and controversial newspapermen of the New Deal era and the original partner of Drew Pearson in writing the "Washington Merry-Go-Round" column, was found dead Monday evening in the bedroom of his Georgetown home.

Dr. James L. Luke, the D.C. medical examiner, said the cause of death was a suicide by gunshot wound to the head. Mr. Allen had suffered from cancer.

Known widely as "Colonel," the Army rank he achieved as an intelligence officer on the 3rd Army staff of Gen. George S. Patton Jr. during World War II, Mr. Allen served in the calvary during the Mexican border campaign of 1916-17 and in France during World War I.

Born in Kentucky, he began his newspaper career in the 1920s on newspapers in Wisconsin, where he attended the state university. Attending the University of Munich on a scholarship in 1924, he covered Adolf Hitler's beer hall putsch and subsequent trial for several American newspapers.

Returning to the United States, he joined the old United Press and later the Washington bureau of The Christian Science Monitor. In 1930, he joined Drew Pearson, then a Baltimore Sun correspondent, in anonymously writing a book, "The Washington Merry-Go-Round," which irreverently portrayed the capital and many of its political and social notables. When their identities were learned, both authors were fired from their jobs.

In 1932, the two teamed to write the nationally syndicated "Merry-Go-Round" column, while Mr. Anderson took on additional duties as Washington bureau chief of the old Philadelphia Record. Mr. Allen continued those connections until he entered the Army after Pearl Harbor. He wrote and collaberated in several other books on governmental and political subjects.

Originally a political liberal, Mr. Allen swung in his later years to a nationalistic conservatism with an emphasis on strong national defense -- a position that apparently stemmed from his service under Gen. Patton.

During combat, Mr. Allen lost his right arm. His military decorations included the Silver Star, the Bronze Star, the Legion of Merit, the Purple Heart, and the French Legion of Honor and Croix de Guerre.

After returning to civilian life, Mr. Allen decided against rejoining Drew Pearson, who in a 1946 column paid tribute to his former partner.

"Bob's battles were always for the underdog -- Nicaragua, the little countries, the public which sometimes gets in the neck," Pearson wrote. "No cause was too hopeless . . . Bob was always putting burrs under sleepy senators. He would walk into their offices, pound on their desks and demand that they get out on the Senate floor and fight. . ."

Pearson died in 1969 and their column, without the original title, is being carried on by Jack Anderson. Mr. Allen ceased his writing last year.

Mr. Allen was a member of the National Press Club and its American Legion Post.

1929, he married Ruth Finney, a columnist for the Scripps-Howard newspaper chain and correspondent for its western papers.She died in 1979. He has no immediate survivors.