As internal attacks on the Syrian government of Bashar al-Assad make progress, Syria’s potent arsenal of chemical weapons confront President Barack Obama with a dilemma.

Mr. Obama has made it clear that he does not want to intervene militarily in the Syrian civil war, though he does want Assad to leave.

But if the United States does not move, in concert with other NATO nations, to neutralize the threat — an act that could require military intervention — they could be used against Turkey, a NATO ally. Or they could fall into the hands of jihadist groups who have joined the fray to seek advantage in Assad’s potential fall.

Neither outcome would be acceptable. Anti-Assad forces, including jihadists from a number of nations, use Turkey as a staging ground for their attacks, and Syria has clearly threatened to use the weapons against any forces seeking to invade.

Meanwhile, on Monday the deputy head of the Organization for the Prohibition of Chemical Weapons told Reuters that its international inspectors “are in preparedness” for being quickly sent to Syria’s borders if needed.

Syria’s statements on the topic have not been, to say the least, reassuring. A Syrian spokesman said last week that the regime would not use the weapons — “if there are any” — against “its own people under any circumstances.”

But what about other nations?

Recent Western intelligence reports that Syria is moving chemical weapons from stockpiles for possible deployment on delivery vehicles.

That prompted President Obama to address Assad last week with this strong warning: “The use of chemical weapons is and would be totally unacceptable. If you make the tragic mistake of using these weapons, there will be consequences.”

NATO officials repeated the warning and authorized the “defensive” deployment of Patriot anti-air and anti-missile defenses to the Turkish side of the Syrian border. The missiles will be installed in coming weeks. Their “defensive” nature could, however, be double-edged if the protection they offer allows a larger build-up of anti-Assad forces in the area.

That brings up the other horn of the chemical-weapons dilemma: What if they fall into the hands of al-Qaida-affiliated groups that have gathered large jihadist forces in Syria? What is going to prevent these forces from getting their hands on some of the weapons, which could make potent terrorist attacks against the West possible?

This dilemma is partly due to President Obama’s insistence on taking a very low profile in the Syrian conflict. Now that decision has come back to haunt him.

As Jackson Diehl, editorial page editor of The Washington Post, wrote in a recent column: “What began as a peaceful mass rebellion against another Arab dictator has turned, in the absence of U.S. leadership, into a brutal maelstrom of sectarian war in which al-Qaida and allied jihadists are playing a growing role. Obama’s light-footprint strategy did much to produce this mess; without a change of U.S. policy, it will become, like Bosnia for Bill Clinton or Iraq for George W. Bush, the second term’s ‘problem from hell.’ ”

And the problems presented by Syria, including what will happen to its chemical weapons, present rising dangers far beyond that troubled nation’s borders.