Chemical weapons were responsible for killing more than 85 people in the Syrian town of Khan Sheikhoun - the worst attack of its kind since the one in 2013 that left at least 1,200 dead in the Damascus suburb of East Ghouta.
For a civil war that has claimed hundreds of thousands of lives, the deaths of 85 more people would usually just have become part of some mind- numbing but ultimately meaningless tally. If not for the use of banned chemical weapons, the latest episode in Idlib province would quickly be forgotten by a world that's already become desensitized to seeing statistics of more war victims.
However, not only must the culprit be condemned, it must also be held responsible.
Russia is militarily active in the region. But the Syrian armed forces of President Bashar al-Assad are the primary suspect, as only the government's forces have that kind of aerial firepower.
Witnesses said the apparent use of deadly sarin gas occurred during air strikes that didn't spare even hospitals.
For the first time since US President Donald Trump's inauguration, Washington has disagreed with the Kremlin.
Trump pointed the finger at Assad, accusing him of crossing "many red lines." But Trump's friend - Russian President Vladimir Putin - defended his close ally, Assad, asserting the chemicals belonged to the rebels fighting the Syrian government forces.
Despite the open disagreement, Trump seemed reluctant to rock the boat with the Kremlin, exercising sufficient self-restraint not to call out Russia as he delivered a warning of retribution that was unspecified and, many fear, unfulfilled.
Aren't politicians hypocritical?
In a world full of lies, it's important not to be fooled by disinformation. In fact, it isn't difficult to establish the truth if international experts were allowed to enter Syria to investigate. The United Nations has accumulated sufficient experience and expertise in this area. In the past, the UN Joint Investigative Mechanism, for example, concluded that Syrian armed forces were responsible for three chemical attacks in 2014 and 2015.
But statements alone - however strong the rhetoric - will be rendered meaningless if it isn't backed by action after the probe. The action must be strong enough to deter further use of chemical weapons.
The major stumbling block is: can the UN achieve this without Putin's cooperation?
It's plain that, emboldened by recent political developments in both Washington and Moscow, Assad is making steady progress in his fight against the rebels. So, it may be asked why it's necessary for the Syrian strongman to resort to chemical weapons and risk world condemnation.
An American political watcher recently pointed out that these attacks follow a pattern - after a chemical attack, there would be a second wave of conventional bombardments. The chemical gas is meant to flush resistance forces and civilians out of buildings to open areas so that conventional bombs can target them more effectively.
The military tactics have proven effective in eliminating militants holding out in Syrian territory. The additional benefit for the Assad regime is that chemicals can terrorize the oppressed subjects to make them more submissive.
As long as Putin provides protection, and Trump turns his attention away from the Middle East, Assad will continue to use chemical weapons against his own people.