The world is witnessing a humanitarian catastrophe of historic proportions. It is happening in Syria. It is being perpetrated by the president of Russia, Vladimir Putin, in support of his protégé, Bashar al-Assad. Russian planes are bombing the civilian population of Aleppo, the country’s second-largest city, to assist Syrian government forces that are attempting to take control of rebel-held areas of the city.

The combined assault has, among other things, killed hundreds of people and wounded over a thousand, put the city’s remaining hospitals out of commission, and deprived the population of drinking water.

President Putin is moving aggressively to exploit the three months between now and the January 20 U.S. presidential inauguration, based on a callous political calculation. As the New York Times puts it: "Mr. Putin calculates that the departing President Obama will be unlikely to intervene in the escalating Syrian conflict and a new American president who might consider a tougher policy will not yet be in office. 'Putin is in a hurry before the American elections,' said Nikolai V. Petrov, a political scientist in Moscow. 'The next American president will face a new reality and will be forced to accept it.'"

Other articles in the New York Times and elsewhere have vividly depicted the suffering of the people of Aleppo and the heroic efforts of the doctors and civilians like the White Helmets who are risking their lives to help them. When the facts are fully established, Putin’s bombing of Aleppo will be viewed as among the modern world’s most egregious war crimes.

I appeal to the people of Russia, the U.S., Europe, and the rest of the world not to stand idly by, but to spread the word and voice their outrage. An outpouring of public opinion could induce President Putin to put an end to his heinous crime against humanity.