MOSCOW — Russia has made its opposition to military intervention in Syria vehemently clear. The foreign minister, Sergey V. Lavrov, warns daily about the risk of an escalating conflagration. A deputy prime minister said the West dealt with the Islamic world like “a monkey with a grenade.” A few commentators on the fringe have warned of World War III.

The one voice that has remained silent, though, is the one that matters most.

President Vladimir V. Putin has conspicuously avoided public comment on reports of a chemical weapons attack on civilians outside of Damascus, the Syrian capital, on Aug. 21, which killed hundreds of people. Instead he has carried on, like many ordinary Russians, as if the civil war in Syria had not reached an ominous new phase. In the days after the attack, Mr. Putin attended a ceremony for the restoration of a fountain made famous in World War II, visited a breakaway province of neighboring Georgia and toured a mine and dam in Siberia.

There is no doubt about Mr. Putin’s opposition to retaliatory strikes. Nor about his support of the government of President Bashar al-Assad in a conflict Mr. Assad has described as a war against Islamic extremism.

Mr. Putin’s public reticence, though, reflects a calculation that Russia can do little to stop a military intervention if the United States and other countries move ahead without the authorization of the United Nations Security Council — and that he has little to lose at home, at least, if they do.