NEW YORK -- James Burnham, 82, a former leftist intellectual who was a founding editor of the conservative National Review, died of cancer July 28 at his home in Kent, Conn.

President Reagan, who awarded Mr. Burnham the Presidential Medal of Freedom in 1983, remembered the former New York University professor as a "skilled and fearless champion of human liberty."

Mr. Burnham "was one of those principally responsible for the great intellectual odyssey of our century -- the journey away from totalitarian statism and toward the uplifting doctrines of freedom," Reagan said in a statement.

Mr. Burnham was a founding editor of The National Review in 1955 and served for two decades as a senior editor, retiring in 1977 after a stroke. He remained as a contributing editor until his death.

"Burnham was absolutely vital to the development of American conservative thought," said William F. Buckley Jr., the magazine's editor-in-chief. "I would consider him the number one intellectual influence on The National Review. He was also a great personal teacher, a remarkable intelligence."

Mr. Burnham was born in Chicago. He graduated with highest honors from Princeton University and did graduate study at Oxford University.

His fascination with Trotsky grew out of the economic chaos of the Great Depression when he was a professor of philosophy at New York University. In 1940, he explained his change of mind in these words:

"The basic reason for the break was my conclusion that Marxism was false and Marxist politics in practice lead not to their alleged goal of democratic socialism but to one or another form of totalitarian despotism."

His embrace of American conservatism took hold in the 1940s and 1950s, as publication of several books brought him to national attention. "The Struggle for the World" in 1947 and "The Coming Defeat of Communism" in 1950 gave popular voice to pessimism about the perils of the Cold War.

Mr. Burnham worked briefly with the Central Intelligence Agency in 1953.

Survivors include two sons, one brother, and seven grandchildren.