Back on May 3, Secretary of State John Kerry issued an ultimatum. He warned President Bashar al-Assad … of ‘repercussions’ if he does not stick to a ceasefire brokered by Russia and the United States and move forward with a political transition aimed at ending Syria’s war.” That political transition was supposed to start on August 1.

Well, it’s now August 2 and there is no transition in sight. Instead, there is unrelenting conflict. As the Wall Street Journal reported: “The Syrian regime and its Russian allies are heavily bombarding hospitals, markets, utilities and aid warehouses in the besieged, rebel-controlled half of Aleppo, according to opposition officials and aid workers who said it was a concerted effort to force rebels and residents to surrender quickly.” Some 300,000 people are trapped in Aleppo, and many will not survive this siege.

So what is Secretary Kerry’s response to the predictable duplicity and depravity of the Assad regime and its backers in Moscow? The Associated Press reported: “At a news conference in Washington, Secretary of State John Kerry said the U.S. would press on with a multi-month effort to prod Syrian President Bashar Assad and moderate opposition groups into a lasting truce and talks on a unity government.”

This report notes that “Kerry’s tone was dramatically different” from early May when he issued an ultimatum to Assad and Putin. Instead, it was pretty much business as usual for Kerry: “Almost all of the time from the moment of the announcement of the target date until today has been consumed by trying to get a cessation of hostilities in place that is meaningful,” he said. “And that is precisely what we are engaged in right now.”

In other words, the Obama administration has let yet another Syria ultimatum pass without doing anything to enforce it. President Obama already did this in 2013 when he laid down a “red line” on the use of chemical weapons. His failure to enforce that ultimatum cost the U.S. credibility. Yet the administration seems to have learned nothing and regrets nothing. It is continuing to issue empty threats as the killing continues to worsen.

Interestingly, something that just happened gives an indication of what the administration could be doing differently at scant cost to the U.S. A Russian helicopter was just shot down near Aleppo. This is reminiscent of the war in Afghanistan in the 1980s when the introduction of U.S. Stingers raised the cost of the conflict to the Russians and made it much more difficult for them to employ helicopter gunships against the mujahideen. The Russians had to resort to less accurate fixed-wing aircraft flying out of Stinger range.

The U.S. and its allies could mount a similar campaign in Syria–with, of course, appropriate safeguards on the employment of anti-aircraft weapons–to significantly raise the costs to the Russians and their Syrian clients of their campaign of terror. With enough anti-aircraft missiles, the rebels could even effectively create their own no-fly zone–although it would be better if the U.S. were to do enforce this because this would reduce the risk of missiles falling into the wrong hands.

Such measures would give bite to Kerry’s words and make Damascus and Moscow pay serious attention to what he says. But the odds of any such thing happening in the waning months of the Obama presidency are remote. This will be a problem from hell that will be inherited by the next president who will have to try to end the killing in Syria while at the same time restoring lost American credibility.