Mark Palmer, former U.S. ambassador to Hungary, later entered business with television stations in Europe and also helped redevelop parts of Washington, D.C. (Family Photo)

Mark Palmer, a forceful and influential diplomat who served as U.S. ambassador to Hungary during the collapse of communism, and who was a chief author of President Ronald Reagan’s 1982 speech declaring that Marxism was headed toward “the ash heap of history,” died Jan. 28 at his home in Washington. He was 71.

He had melanoma, his wife, Sushma Palmer, said.

From his first visit to the Soviet Union when he was 19, Mr. Palmer recognized that the Russian people were different from the Soviet government.

“I profoundly believed that Russians were like Americans,” he recalled in an oral history interview with the State Department in the late 1990s. “I believed that sooner or later they would have a decent political system.”

Building on that belief of shared humanity, Mr. Palmer spent 26 years in the Foreign Service and became the State Department’s top Kremlinologist, or expert on Soviet affairs, in the 1980s.

Throughout his career, Mr. Palmer was known for his advocacy of democratic principles of government. His notions were considered a bit quixotic in the 1970s, when U.S. foreign policy was geared more toward containment of the Soviet threat and monitoring human-rights abuses. But his ideals were vindicated over time, as democracy movements spread from one country to the next.

Mr. Palmer was named U.S. ambassador to Hungary in 1986 by Reagan and carried his campaign for democracy to the streets of Budapest, sometimes marching with forces opposing the communist regime.

“This is the greatest opportunity the West has had to influence this region since the division of Europe after World War II,” he told Time magazine in 1989. “We simply must jump in, not only to advance our own values and economic system but to do all we can to assure that these dramatic changes come with maximum stability.”

Mr. Palmer’s support of the Hungarian opposition movement lent credibility to its cause, but his close ties with dissidents sometimes led to reprimands from his State Department bosses.

Earlier in his career, Mr. Palmer was the sole speechwriter for Secretary of State Henry A. Kissinger from 1973 to 1975. He was also a primary author of Reagan’s 1982 speech to the British Parliament in which the president outlined a goal of spreading democracy throughout the old Soviet bloc.

“It is the Soviet Union that runs against the tide of history by denying human freedom and human dignity to its citizens,” Reagan said in one of his most celebrated speeches. “What I am describing now is a plan and a hope for the long term — the march of freedom and democracy which will leave Marxism-Leninism on the ash heap of history.”

Mr. Palmer also organized the 1985 Geneva summit between Reagan and Soviet leader Mikhail Gorbachev, which was considered a diplomatic breakthrough that led to a thawing of relations between the two superpowers.

“His passion was clearly freedom, and he was passionate about seeing the remaining walls of dictatorship fall,” Andras Simonyi, Hungarian ambassador to the United States from 2002 to 2007, said in an interview. “It’s not too much to say that the democracies of central Europe owe a lot of debt to Mark Palmer.”

Robie Marcus Hooker Palmer was born July 14, 1941, in Ann Arbor, Mich. As the son of a naval officer, he moved many times during his youth and graduated from a private high school in Vermont.

Mr. Palmer majored in Russian studies at Yale University and took courses in the Soviet Union. He was a Freedom Rider in the South during the civil rights movement and organized demonstrations in Baltimore, Atlanta and Alabama.

After graduating from Yale in 1963, he worked as a newspaper and TV journalist in New York before joining the Foreign Service in 1964. In addition to overseas assignments in New Delhi, Moscow and the former Yugoslavia, Mr. Palmer wrote speeches for three presidents and six secretaries of state and was the author of widely used State Department handbooks for diplomats and military officers.

He received three presidential awards, but Mr. Palmer left the Foreign Service under pressure in 1990 after he was recruited to lead a new Western-financed business venture in Eastern Europe. The move was interpreted as a conflict of interest by several members of Congress and by some of his State Department supervisors.

Mr. Palmer said he followed State Department procedures, but he ended up spending $60,000 in legal fees to defend his name.

“I waited for about a year to see whether the department would ever have the decency to apologize to me for what I’d been put through,” Mr. Palmer said in the 1998 oral history. “Nothing. Never a word.”

After leaving the Foreign Service, Mr. Palmer was based in Berlin as president of the Central European Development Corp. He spearheaded business enterprises throughout the old Soviet empire and established the first independent TV stations in six Eastern European countries. He also owned a company involved in building housing in Anacostia and other reviving areas of the Washington region.

Survivors include his wife of 47 years, Sushma Mahyera Palmer of Washington, and a sister.

Mr. Palmer held leadership positions with groups dedicated to promoting the principles of democracy, including Freedom House.

He also wrote the 2003 book “Breaking the Real Axis of Evil: How to Oust the World’s Last Dictators by 2025,” which was praised in a Wall Street Journal review as “one of the best but least noticed books among all the tomes addressing the quest for peace in the post-Sept. 11 era.”

Then-Rep. Thomas Paul Lantos (D-Calif.), a sponsor of the Advance Democracy Act of 2007, designed to promote international democratic movements, said the book was a key theoretical framework of the congressional bill.

To the end, Mr. Palmer believed that the United States had a responsibility to foster grass-roots freedom and democracy movements wherever they arose.

“If people were allowed to voice their views,” he told the Christian Science Monitor in 2003, “the dictators would not stay, and in that sense they are very fragile. The last 30 years of history shows that they go fairly easily when people start to get organized.”