It is not the first such monument, but it is the first built by presidential decree. A chunk of rock from the Solovki labor camp, the first in what became the national gulag system, sits in front of the Lubyanka Square headquarters of the secret police.

In September, at Butovo, an estate near Moscow, a wall bearing the names of about 20,000 victims shot there was opened as part of a memorial garden.

Confronting the harrowing legacy of government repression, especially the labor camps, has long been a contentious issue.

Those who want a full vetting of the crimes of the past argue that the future will be hobbled without a thorough reckoning. Opponents call the subject too divisive and say it is best forgotten. They include, in particular, members of the Communist Party and a growing number of people who consider the bloody purges under Stalin a necessary if harsh means needed to modernize the country.

An estimated 750,000 people were executed during the height of the Great Terror, in 1937 and 1938, but the victims number in the millions when the labor camps, forced collectivization, famine and other horrors are taken into account.

Given that the machinery of state repression was run by the ancestor agencies of the Russian security service, the F.S.B., which still controls Russia, historians and others hold out little hope for a thorough examination.

The struggle is constant. The administration of the Gulag Museum said it was currently wrestling for control of a building near Lubyanka whose new owner has plans to turn it into a high-end perfume store.