Editor's note: George A. Lopez is the Hesburgh Chair in peace studies at the University of Notre Dame's Kroc Institute for International Peace Studies.
(CNN) -- Secretary of State Hillary Clinton's warning of a "red line" to deter the al-Assad regime's use of chemical weapons exposes several fault lines in the West's response to the crisis in Syria.
In light of the activities around Syria's chemical weapons sites recently, the Obama administration's admonition seems necessary and rational. But the hope to influence the short-term behavior of President Bashar al-Assad carries some immediate implications that, until now, the U.S. and its allies have largely avoided.
Clinton's words are strong pressure on the regime that it must not cross that line. Meanwhile, the West needs to make some strategic moves. The first would be a robust diplomatic effort -- in which the Russians could play a significant role -- that encourages members of the regime to exchange their protected departure from Syria for a cease-fire and international control of the weapons.
A declaration of the high political value of the chemical stockpile may well drive a wedge between al-Assad -- who has claimed he will not leave Syria alive -- and those government officials who do not share his endgame.
But if this direction of diplomacy fails, then the much less preferred -- but necessary -- option of military action to secure the chemical weapons should be seriously considered.
This approach would plunge the West into another fault line. Various rebel leaders consider any weapons bargain as revealing the West's true colors. To wit: The U.S. will intervene to prevent the chemical weapons from "falling into the wrong hands," but President Obama has so far rejected intervention, leaving 40,000 Syrians to die in al-Assad's killing machine, according to opposition activists.
In order to address the rebels' distrust and disdain, the U.S. must make it clear that it stands by its own words, or as Obama said, "if you make the tragic mistake of using these weapons, there will be consequences, and you will be held accountable."
Syria did not sign the 1992 chemical weapons convention and hid and lied about its stockpile of nerve agents and mustard gas. Its no-use pledge in July was a projection of government power rather than a stake in moral high ground.
Al-Assad has shown time and again that he is willing to kill his way out of the Syrian crisis. We can assume that red lines do not matter to him. Patriot missiles may well deter or knock out Syrian missiles a few weeks from now. But this regime may have chemical weapons in canisters suited for firing from anti-tank guns or even shoulder-mounted launchers. This is the danger that must be addressed as rebels head into Damascus.
From the beginning of the uprising, al-Assad has maintained that those taking up arms against the government were foreign terrorists. No NATO nation doubts that non-Syrians are fighting among the rebels.
Those who believe that rebel control of the Syrian-Turkish border now provides international agencies an opportunity for direct humanitarian relief as winter descends on desperate refugees must be careful. In its last disclaimer about chemical weapons, the regime said it would use them only if the nation faced foreign intervention.
Al-Assad's sick logic leads to only one viable conclusion: He could well use chemical weapons against rebel forces entering Damascus or along the Turkish border soon.
There's a final fault line. Western human rights analysts who have argued for more robust action to protect civilians are rightfully raising new concerns about the brutality of the situation in Syria. Specifically, revenge violence and massive political execution may await al-Assad's supporters in Damascus should the rebels triumph. Should this happen, this horrific conflict will become even more bloodstained. Will the West just look on?
The red line highlights the tensions in the Syrian crisis to their breaking point. This leaves the West no real alternative other than significant intervention. And it must happen soon.
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The opinions expressed in this commentary are solely those of George A. Lopez.