The civil war in Syria between forces loyal to President Bashar al-Assad and opponents representing a variety of political, ethnic and religious affiliations (some democratic and some not), may be taking a turn that greatly raises its international impact.

Indeed, despite the “lessons” of Iraq and Afghanistan, the United States may be coming close to committing significant military forces in the region again — or at least engaging in a Libyan-style air war over Syria itself.

That possibility exists because the war may soon escalate in a way that violates U.S. policies opposed to the use of specialized, highly lethal weapons in the region.

So far, the nearly 2-year-old conflict, in which more than 30,000 fighters and civilians have died, has been waged with conventional weapons.

But intelligence agencies are now warning that Assad’s forces appear to be moving and preparing chemical weapons in government arsenals.

Nerve gas, mustard gas and other chemical agents make up one of the three types of “weapons of mass destruction” (which also include biological and nuclear weapons).

And the threat of the use of gas weapons raises the stakes in the conflict, which has threatened to spread over the borders of adjacent nations such as Jordan, Turkey and Israel.

The latter two nations have exchanged gunfire with Syrian loyalist forces, and thousands of anti-Assad Syrian refugees have taken shelter in camps in Turkey and Jordan.

The involvement of Turkey also raises the chance of Western engagement, since it is a NATO member and there have already been preparations made to move NATO Patriot anti-missile units to the Syrian border.

Now, President Obama has opened the door to wider U.S. involvement, warning Assad that the use or distribution of chemical weapons would result in “consequences” in which he “would be held accountable.”

The import is clear; the United States will take direct action to limit or halt the use of such weapons.

There is likely very little desire by Americans to replicate the level of forces used in Iraq or Afghanistan.

However, if the use of WMDs doesn’t bring a swift international response, the lid comes off and the chances of their use or diversion elsewhere rise exponentially.

Thus, stopping their use and export is rightly a top U.S. goal in the region.