MOSCOW — Anatoly Chernyaev, an influential foreign policy adviser and speechwriter for Mikhail Gorbachev who argued passionately for military de-escalation and political openness while keeping a poignant, detailed personal diary of his observations during the final two decades of the Soviet Union, died March 12 in Moscow. He was 95.

The Gorbachev Foundation confirmed the death. Family members said he had been suffering from a respiratory illness.

Chernyaev, a World War II veteran who spent decades rising through the ranks of the Kremlin’s foreign policy establishment, came to larger attention as a member of a liberal circle of advisers to Gorbachev from 1986 until the fall of the Soviet Union in 1991.

Among Gorbachev’s most trusted confidants, he was a tireless proponent of the “new thinking” that would reform the Soviet Union after years of stagnation, demilitarizing its foreign policy and seeking glasnost, or openness, at home.

He urged Gorbachev to seek a historic reduction in nuclear arms with the United States; supported an immediate pullout of Soviet troops from Afghanistan, which the Russians invaded in 1979; and, as early as 1986, proposed considering the prospect of a unified Germany.

He was at Gorbachev’s summits with President Reagan, British Prime Minister Margaret Thatcher and others.When the Soviet Union fell, he retreated with Gorbachev to the Kremlin to make mournful toasts over cognac. Both had sought reform, not collapse of the Soviet Union.