If Syria, Russia and Iran are right and Israel did in fact carry out an attack on a Syrian air base a day and a half after Bashar Assad’s regime used chlorine gas against civilians in a Damascus suburb, the Jewish state should be proud.On Holocaust Remembrance Day, as Israel commemorates the destruction of European Jewry at the hands of Nazi Germany and its allies in Vichy France, Austria, Romania, Slovakia, Hungary, Poland, Ukraine and elsewhere, it is essential for the world – and the Assad regime – to know that indiscriminate acts of barbarism will not be tolerated.US President Donald Trump was exercising a healthy moral sense when he responded strongly on his Twitter account to the atrocity committed by Assad’s regime against Syrians in Douma, including women and children.“President Putin, Russia and Iran are responsible for backing Animal Assad. Big price to pay.”Trump’s Tweet should be followed up by military action and it should be backed by all civilized countries, particularly the nations of the European continent on which the Holocaust was carried out. (Russia, which prides itself so much on having destroyed Nazism during World War II, is now protecting the Assad regime and spreading lies that poison gas was not used in Douma.) The point of the military action is not to change the course of the civil war in Syria. Rather, the point of a combined US, European military strike that causes significant damage to the Assad regime’s military capabilities is to make a moral statement and, one hopes, to deter Syria from using poison gas against anyone in the future.What makes the Syrian use of chlorine gas all the more despicable is that it was motivated not by desperation but by depravity. Assad, with the backing of Russia and Iran, has all but won the civil war. Forces loyal to him have surrounded Douma.In any event, the ruthless murder of civilians is rarely if ever a deciding factor in war. In World War II the Axis powers were responsible for the vast majority of deaths – as well as for a disproportionately high rate of civilian killings, in part due to the Holocaust – yet their defeat was total and relatively speedy once the US entered the war.Assad, apparently emboldened by Trump’s declaration that the US plans to pull its troops out of Syria, believed that the world would stand by in indifference, as it has in the past when he used barrel bombs containing chlorine against civilians.Perhaps Assad also thought that the Trump administration’s decision a year ago this month to fire Tomahawk missiles at Syrian army bases in response to his use of Sarin gas was a blip and that the US under a fickle Trump, who was now in the mood for retreat, would not act again alone among the nations.Perhaps he also thought that the US and other nations would make a distinction between the chlorine gas used this week and sarin, the nerve gas developed by the Nazis during World War II.Syria’s Assad and Putin’s Russia must know that they are not above the moral reckoning of the community of civilized nations. The two men lied when they claimed to have handed over all of Syria’s chemical weapons to the Organization for the Prohibition of Chemical Weapons in accordance with a deal reached between the Obama administration, the UN and Russia in 2013. Now they must pay for their lies.Failing to act will send a message to other rogue states and autocratic strongmen that it is possible to lie and deceive in international forums without consequences.It should mean something that Syria is a signatory of a 1997 convention that bans not only the use but also the production of chemical weapons. Syria should be just as compliant as any other country, or face the consequences.Holocaust Remembrance Day is not just a time to commemorate those lost to genocidal hatred, it is a time to remember the many failures of the community of nations that made the Holocaust possible, so that they are not repeated.