“The myth of the Great Patriotic War is the founding myth of contemporary, post-1991 Russia,” said Serhii Plokhii, a Russian-born history professor at Harvard. “Anything that challenges that myth, understood as the victory of the unified Russian people over the hostile West, or introduces shades of gray into the black-and-white picture of the battle between good and evil, is rejected and attacked.”

Mr. Melikhov is not the only one to be singled out. A state committee in Moscow recently vetoed a decision by scholars in St. Petersburg to award a doctoral degree to Kirill Alexandrov, a historian. His dissertation, on the Committee for the Liberation of the Peoples of Russia, an outfit set up in 1944 with German support to rally opposition to Stalin’s regime, was deemed insufficiently patriotic.

Mr. Melikhov believes that his principal crime, as far as officials are concerned, is not just the matter-of-fact treatment of reviled traitors at his museum in Podolsk, and another museum of his near Rostov-on-Don in southern Russia.

A bigger problem, he said, is that any open discussion of the choices Russians made during the war undermines Mr. Putin’s efforts to rally Russia around the heroism of the past and his hostility to the internal and external enemies that the Kremlin presents as besieging the country.

“The Soviet Union collapsed, but the Soviet system of rule and thinking has stayed the same,” Mr. Melikhov said. “There was monopolization of political power, monopolization of economic power, monopolization of mass media, monopolization of civil society. Today, the basic elements of this Soviet system are all being put back in place.”