Smith Hempstone, 77, a conservative syndicated columnist who as U.S. ambassador to Kenya from 1989 to 1993 became an effective, aggressively undiplomatic critic of the country's ruler, Daniel arap Moi, died Nov. 19 at Suburban Hospital. He had complications from diabetes.

Mr. Hempstone was credited with helping usher multiparty elections into an African country that, although a U.S. ally during the Cold War, had little tolerance for political dissent. Moi was Kenya's second president since its independence in 1960, and his Kenya African National Union was by constitutional decree the only legal party.

Mr. Hempstone had covered the advent of Kenya's independence for the Chicago Daily News and wrote two well-received modern histories of the region. He went on to work for the Washington Star, which his mother's family once owned, and the Washington Times, where he briefly was the top newsroom editor in the mid-1980s.

Several of his jobs ended in a personality clash. His service as President George H.W. Bush's ambassador to Kenya was no less testy, a point he appeared to relish by titling his memoir "The Rogue Ambassador."

In Nairobi, Mr. Hempstone advocated the end of KANU dominance. He gave refuge within the U.S. Embassy to a noted human rights lawyer sought by the police and spirited the man, Gibson Kamau Kuria, to safety in London. He also denounced economic corruption, which he said prompted greater furor in Kenya than any human rights matter.

The KANU-backed Kenya Times denounced Mr. Hempstone with a pithy headline: "Shut up, Mr. Ambassador."

He did not.

The foreign minister called the ambassador a racist with the perspective of a "slave owner." Mr. Hempstone denied the charge, noting that the political opposition he championed was also black. He called himself a convenient "blue-eyed demon" for Moi and his cronies.

He later wrote in an op-ed in the Los Angeles Times, "I declared to a notorious revolutionary forum, the Rotary Club of Nairobi, that America would in the future concentrate its finite economic aid on 'those countries that cherish human rights, adhere to the rule of law and practice multi-party democracy.'

"The same day, two former Kenyan Cabinet ministers, Kenneth Matiba and Charles Rubia, announced the formation of the Forum for the Restoration of Democracy, demanded the legalization of opposition parties and called for elections."

After increasing condemnation from abroad and withholding by major lending agencies, Kenya held free elections in late 1992. With opposition parties splitting the results, Moi received 36 percent of the vote and won five more years in office. After another election win in 1997, Moi stayed in office until 2002.

Lawrence S. Eagleburger, the former secretary of state, described Mr. Hempstone yesterday as "a man of real courage" and said he was kept on in Nairobi, despite his public brawls, because "to have pulled him out or to have disciplined him would almost certainly have created real problems politically at home."

Mr. Hempstone was not above reproaching U.S. policy in the region and once sent a prescient, if impolitic, note to his superiors warning the Bush administration against sending a humanitarian mission to Somalia.

Smith Hempstone Jr. was born Feb. 1, 1929, in Washington, where his father was stationed as a Naval officer. He graduated from Indiana's Culver Military Academy and the University of the South.

After Marine Corps service during the Korean War, he spent four years in Africa as a fellow of the Institute of Current World Affairs. The institute had a long affiliation with the Chicago Daily News, and Mr. Hempstone became the paper's Africa correspondent in the early 1960s.

During that period, he wrote "Africa: Angry Young Giant," a survey of 26 countries; and "Rebels, Mercenaries and Dividends," about the attempted secession of Katanga, the mineral-rich southern province of the Democratic Republic of Congo.

He won a Nieman fellowship at Harvard University, wrote two novels and in 1966 became the Washington Star's London-based reporter, covering Europe and the Middle East.

He rose to editorial page editor but left in 1975 after disagreements with Joe L. Allbritton, the paper's new owner. He began self-syndicating his column, "Our Times," which at its peak ran in 90 newspapers.

In recent years, Mr. Hempstone faced a libel lawsuit stemming from his diplomatic memoir. He accused Moi and a top aide, Nicholas K. Biwott, of orchestrating the killing of Robert Ouko, a former foreign minister who fell out of favor with the president.

Moi later withdrew his suit, but Biwott won a substantial judgment from a Kenyan court in 2002. U.S. Embassy officials in Kenya have told Mr. Hempstone's family that they did not accept the court's jurisdiction but advised Mr. Hempstone not to return to Kenya.

Survivors include his wife of 52 years, Kathaleen Fishback "Kitty" Hempstone of Bethesda; a daughter, Katherine Hempstone of Baltimore; and a grandson.