The bodies and debris that rained from the Ukrainian sky offer a cautionary lesson about the danger of giving heavy weapons to non-state actors. I hope the hawks who wanted President Obama to ship anti-aircraft missiles to the Syrian rebels are paying attention.

By now there is little doubt that Malaysia Airlines Flight 17, with 298 people on board, was blasted out of the sky by a Russian-made SA-11 missile fired from eastern Ukraine. U.S. officials say they have solid evidence that Russia supplied such arms to the separatist rebels who control that part of the country.

It was deeply irresponsible for Russian President Vladimir Putin to put a missile system capable of downing a civilian airliner at the disposal of trigger-happy separatists who may have had no idea what they were shooting at. If Putin believed the presence of Russian advisers would foreclose the possibility of a tragic mistake, obviously he was wrong.

The tragedy comes amid Putin's broader campaign to fragment Ukraine and reabsorb parts of it into Russia. This whole effort should be condemned and resisted; Russia has already been hit with international sanctions, which now are likely to be toughened. "The costs for Russia's behavior will only continue to increase," President Obama said Monday.

The most important lesson U.S. policymakers should learn from this terrible event, I believe, is that sophisticated weapons, once given to combatants in a civil war, are virtually impossible to keep under control. This is true whether those given the arms are Russian-backed rebels or "moderate" Syrian freedom fighters.

Of particular concern are anti-aircraft weapons. In any civil war, the government side is likely to have superiority or supremacy in the air. Governments have professional air forces and fleets of aircraft; rebel armies generally do not.

In Ukraine, the separatists sought to neutralize the government's advantage in air power by deploying anti-aircraft systems — and successfully using them. On July 14, just days before the Malaysia Airlines tragedy, a Ukrainian troop transport plane was hit by a missile near the Russian border. This aircraft — like the civilian airliner — was flying above 20,000 feet, high enough that it could only have been downed by a powerful and sophisticated anti-aircraft system such as the SA-11.

But of the dozen government aircraft reportedly shot down by rebels in recent months, most were flying at lower altitudes. In late May, for example, a helicopter with 12 soldiers aboard was downed. In June, 49 Ukrainian troops died when a transport plane was blown out of the sky.

These other aircraft were within the range of small, portable, shoulder-fired missiles, which Russia is believed to have supplied to the separatists in large numbers — and which hawkish critics of Obama's foreign policy have demanded he give to pro-Western rebel groups in Syria.

The government of Bashar al-Assad has survived largely through the brutal use of air power against defenseless civilians. Partly neutralizing this advantage — by credibly threatening to shoot Assad's planes down — might have changed the course of the war, though now it might be too late.

From the beginning, Obama has been extremely reluctant to send anti-aircraft weapons of any kind into Syria. Now his critics should understand why.

When weapons are given to non-state actors, there is no guarantee they will be used competently — and no guarantee that they won't fall into the wrong hands.


Eugene Robinson is a columnist for The Washington Post.