AS THE CHALLENGE from Iran has grown, the United States and its allies have repeatedly been tantalized by the possibility of driving a wedge between Tehran and its chief Arab ally, Syria. The two countries work together to sponsor the Hezbollah movement in Lebanon and Hamas in the Gaza Strip; removing Syria from the equation could cripple Iran's bid to become the dominant power in the Middle East. The problem is how to move the murderous and corrupt regime of Bashar al-Assad, which hosts Hamas's leadership and is under investigation by the United Nations for assassinating Lebanese politicians. Sanctions against Syria have been too weak to be effective, and most of the political bribes that might interest Mr. Assad would be self-defeating -- such as allowing him to restore Syria's political hegemony over Lebanon.

Oddly, the key to unlocking this puzzle may be held by Israel, Syria's mortal enemy. A central Syrian goal remains recovering the Golan Heights, territory captured by Israel in the 1967 war. In the past, Israel has been willing to discuss the return of the Golan Heights in exchange for a peace settlement with Damascus; in 2000, a deal broke down over the question of a few hundred yards of disputed territory along the Sea of Galilee. Now Israel has a larger incentive than ever to negotiate: its preoccupation with Iran and its Lebanese and Palestinian proxies. Israeli Prime Minister Ehud Olmert's decision to begin exploratory talks with Syria a year ago, using Turkey as an intermediary, was a logical one.

What remains unclear is whether either side seeks more than short-term tactical gain from the talks, which were publicly revealed by the two governments late last month. For Syria, the public announcement of the talks -- which it pressed for -- eases the isolation that the Bush administration has tried to impose on Mr. Assad and distracts attention from his continuing campaign of murder in Lebanon. Soon after the announcement, several European governments resumed their contacts with Damascus. For its part, Israel calculates that even the suggestion of a peace deal must place strain on relations between Damascus and Tehran. And Mr. Olmert, in danger of criminal indictment, also benefits from a change of subject.

For now, it's difficult to believe that either side is willing or able to strike a larger bargain. In the absence of a convincing demonstration of change in Syria's strategic orientation, most Israelis and their representatives in parliament will strongly oppose giving up the Golan. Mr. Assad has become so deeply enmeshed in his alliance with Iran and in criminality in Lebanon that he is almost certainly incapable of such a switch. He recently told a visiting British delegation that asking for a rupture in his ties with Iran was comparable to demanding a break between the United States and Israel. If that's true, the talks Turkey is sponsoring will prove to be another dead end.