There's little that honourable Western politicians can say in response to Tuesday's chemical attack, apparently carried out by the Syrian government, against civilians near the city of Idlib in northern Syria. But if they have a shred of decency, when issuing the obligatory statements of sorrow and condolence, they will not profess to be shocked.

This attack, whose victims include asphyxiated children with no obvious injuries save internal ones causing them to foam at the mouth, was — if banned chemical weapons were in fact used — a war crime. But it is not at all surprising. Honest people do not claim to be shocked by the inevitable.

The 'red line'

Former President Barack Obama erred in 2012 when he said the use, or even movement, of chemical weapons in Syria was a "red line" for his administration that would trigger "enormous consequences."

The problem with declaring that a certain action constitutes a red line is that it implies everything else is permitted. And, indeed, Syrian President Bashar al-Assad slaughtered Syrians using mostly conventional weapons for about a year following Obama's threat. Then Assad tested the American president. His forces used poison gas against the rebel-held Damascus suburb of Ghouta, killing hundreds, including children.

Assad called America's bluff and won, and the Russians had to broker a deal. (SAUL LOEB, NATALIA KOLESNIKOVA/AFP/Getty Images)

Obama threatened strikes against Assad's regime, but backed down when Russia brokered a deal that would supposedly see the Syrian government give up its stockpiles of chemical weapons. That was when another chemical attack, or an equally horrendous atrocity, became inevitable. Assad had called America's bluff and won. No threat Washington might make after that could ever be credible.

Since then, Assad's forces have regularly launched chlorine gas attacks. Chlorine gas, however, rarely kills unless its victims are in an enclosed space. Tuesday's attack, for which Syria has denied responsibility, involved a far more deadly substance, and killed even those caught in the open.

Blame does not end with Obama. But current U.S. President Donald Trump cannot be accused of Obama's naked hypocrisy regarding Syria. While Obama rushed to declare that Assad should step aside (when it looked like he might soon be toppled) but then did little to advance such an outcome, Trump has been consistent in his stated belief that however distasteful Assad's regime might be, its actions aren't really of America's concern.

We should stop talking, stay out of Syria and other countries that hate us, rebuild our own country and make it strong and great again-USA! —@realDonaldTrump

If Assad worried at all that America might be provoked into intervention, such fears likely dissipated last week when Secretary of State Rex Tillerson said Assad's fate "will be decided by the Syrian people."

This, of course, was disingenuous. Assad's fate, and the fate of the Syrian people, is being decided in large part by Russian President Vladimir Putin, whose military has intervened in Syria on the side of the Syrian government. But Tillerson's remarks sent Assad a reassuring message, one that was made explicit when Nikki Haley, U.S. ambassador to the United Nations, said America's priority "is no longer to sit there and focus on getting Assad out."

Assad surely knew then he could again gas children without fearing the consequences.

Bloody public relations

Assad has long sought to portray the choice in Syria as one between him or the jihadists of Islamic State. He's bolstered this argument by targeting other rebel groups with far greater intensity than he does Islamic State. He's been helped in these efforts by Russia's air force which, like Assad's, has mostly bombed rebels that threaten Syrian government forces rather than the Islamic State in the deserts of eastern Syria.

Assad's bloody public relations efforts worked on Donald Trump and, from Assad's perspective, that's all that really matters. Syria's rebels will not defeat Assad on their own so long as Russian planes are dropping bombs on his behalf. Whatever support Syrian rebels enjoy from Qatar, Turkey and other outside countries does not match the help that Russia and Iran have given Assad. Shifting the balance of power in Syria would require U.S.-led intervention. That's not going to happen, and no other country is going to hold Assad to account without Washington's lead.

After six years of war, Assad is arguably more secure than he has been since the conflict began.

This latest chemical weapons attack will drive more Syrians out of the country. They will become refugees and may fall under the care of international NGOs and United Nations agencies that are funded with hundreds of millions of dollars by Canada and other wealthy nations. This support is necessary and good, but it's also atonement for doing so little to prevent conditions that create refugees in the first place.

What's caused them to flee is shocking. But for those who have allowed it to happen, the only appropriate response is shame.

This column is part of CBC's Opinion section. For more information about this section, please read this editor's blog and our FAQ.