PRESIDENT OBAMA boasted in his State of the Union address last week that “American diplomacy, backed by the threat of force, is why Syria’s chemical weapons are being eliminated.” In theory, the statement is correct, but in practice, the landmark effort to destroy an entire stockpile of dangerous chemical weapons has stalled. If the effort cannot be put back on track, it will raise anew the question of whether Mr. Obama is still serious about his “threat of force.”

No one should be surprised that the international effort is behind schedule. The original deadline to remove all so-called Priority One chemicals, the most dangerous, by Dec. 31, and all Priority Two chemicals by Feb. 5, was terribly ambitious for an operation that is complex even in peacetime and doubly difficult in the midst of a civil war. The chemicals must be transported to the coast, then by sea to a destruction facility on board a U.S. vessel, the MV Cape Ray, and neutralized safely.

But the effort has stalled. Syria has failed to fulfill its part of the deal, moving only 4 percent of the chemicals to the port at Latakia. According to a statement made Wednesday by the United States to the executive council of the Organization for the Prohibition of Chemical Weapons in the Hague, Syrian President Bashir al-Assad is, in effect, slow-walking the chemicals in order to obtain more security equipment. U.S. Ambassador Robert P. Mikulak told the council that Syria has demanded “armored jackets for shipping containers, electronic countermeasures, and detectors for improvised explosive devices.” He said the demands are “without merit” and “display a ‘bargaining mentality’ rather than a security mentality.”

Mr. Assad’s gambit is unacceptable. The chemical weapons removal was the direct outgrowth of the use of poison gas to kill more than 1,400 people last year, including women and children. The evidence pointed directly at Mr. Assad’s forces for use of the chemical weapons. Further delay by Syria in the movement of these deadly substances to the coast will only compound Mr. Assad’s complicity in the grave crime of the original attack.

Mr. Mikulak also pointed out that Syria now seems to be trying to avert efforts to destroy seven hardened aircraft hangars and five underground structures. Syria has offered to weld the doors shut, which can be quickly undone. The United States has insisted, correctly, on more destructive measures that cannot be reversed.

We thought that chemical weapons demilitarization in Syria was a worthy, if risky, cause. Now, just months later, it appears that Mr. Assad is playing games. This cannot be tolerated. Mr. Obama has been noticeably adverse to direct U.S. military action in Syria, but if Syria continues to treat the chemical weapons as a bargaining chip, the threat must be made real, and used if necessary. Russia, Syria’s patron, claimed Friday that Mr. Assad is “acting in good faith.” Rather than provide such cover, it ought to swiftly persuade Mr. Assad to quit this reckless game of chicken.