Last Monday, a Saudi newspaper, Okaz, published a story claiming that the latest United Nations report on the assassination of former Lebanese Prime Minister Rafik Hariri would directly implicate Syria. It suggested that Ghazi Kanaan, Syria's interior minister who supposedly committed suicide (or, as agnostics put it, "was suicided") last year, had recorded a conversation in which he detailed Syrian involvement in the crime. UN investigators would finger top officials in Damascus, the newspaper predicted, including President Bashar Assad's brother in law.

Two things were interesting in the allegation. First, it proved to be false. While Syria remains the leading culprit in the murder, the UN chief investigator, Serge Brammertz, played his cards close to his chest in his interim report, released on Monday, by failing to accuse anyone. Second, the possible existence of a Kanaan tape was first floated by a leading Syrian witness who had earlier given sworn testimony to the UN commission. The witness in question is believed to be close to the Saudis, even a Saudi tool in the investigation, whatever the veracity of his revelations. The parallels between his assertion and the Okaz article suggested that something was afoot.

The Saudis may also have known that Brammertz would not mention a Kanaan tape. In fact that's more than likely, since the UN investigator has for months imposed a near total blackout on information pertaining to the Hariri case. That's why it is reasonable to ask whether, in running the story, the Saudis were not really sending a different message: cautioning Assad that such a tape exists and could be used against him in the future.

Oddly enough, this splendidly Byzantine episode has implications for the United States. Saudi Arabia and Syria are reportedly near, if not beyond, the breaking point in their relations--largely because of Assad's close connection with Iran and his support for Hezbollah, which the Saudi monarchy and the Bush administration see as major threats. Given that the U.S. has few options when it comes to imposing "behavior change" in Syria--the administration's declared strategy--Saudi resentment creates new opportunities for it.

This was brought home to me last June, when I sat with an influential White House official and suggested that the behavior-change-rather-than regime-change mantra as applied to the Assad regime seemed not so much a policy as a bureaucratic compromise within the administration. Syria was not about to change its behavior, and the U.S. wasn't about to bounce Assad. To mask the deadlock, the U.S. had hit on the behavior-change formulation, which would broadly guide American action but probably lead nowhere.

The official disagreed, and underlined that he was waiting for the results of the UN investigation. This may not have been the most compelling of rebuttals, but it showed that some in Washington still saw the truth about Hariri's killing as Syria's Achilles heel.

Back to the Saudis. After Hariri's death in February 2005, the kingdom took a harsh line with Syria. Assad's decision to withdraw his forces from Lebanon followed a tense meeting with then-Crown Prince Abdullah, now the king, who handed the Syrian president an ultimatum. Subsequently, however, Saudi angst took over. With Syria out of Lebanon, Abdullah saw no advantage in destabilizing Assad's regime, as this might have destabilized the region. Riyadh's Syria policy throughout the early part of this year appeared to be run by the foreign minister, Saud Al-Faysal, a man universally recognized as a custodian of Arab immobility.

Though Assad should have been reassured, but he failed to reciprocate. Instead, he translated his growing confidence into closer ties with Iran. Last June, Syria and Iran signed a defense pact, a move that alarmed the Saudis, who fear Iran's hegemony over the Gulf, and its influence over the kingdom's Shiites, even more than they do democratic change. In July and August, Shiite-Sunni tension was on display as Lebanon fell into war. The Saudis publicly condemned Hezbollah for its cross-border abduction of two Israeli soldiers, accusing the party of "adventurism." They later helped engineer an Arab League foreign ministers' meeting in Beirut at which Syria's representative was isolated. The mainly Sunni states of the region saw the event as a means of containing Iran and clipping Hezbollah's wings in favor of the Lebanese government. Syria found itself on the wrong side of the Arab consensus.

The situation only got worse when Assad, in a fiery speech in August, called Arab leaders, without naming them, "half-men" for failing to support resistance against Israel.

The Saudi-Syrian estrangement, or divorce, came amid reports that Saudi decision-making on Syria had shifted away from Saud Al-Faysal to the head of the National Security Council, Bandar bin Sultan, previously the ambassador to the United States. From my conversations with Lebanese politician Walid Jumblatt, who keeps an open line to the Saudis, Bandar has advocated a tougher approach to Syria in their discussions than other royals. Assuming the change in attitude in the kingdom is being mainly driven by Bandar and his side of the ruling family, the U.S. might have more leverage in the near future to raise the heat on Damascus.

But one should never oversimplify with the Saudis. The ultimate decision-maker remains King Abdullah. If it's true that Ghazi Kanaan made an audio- or videotape implicating the Syrian regime, and that the Saudis have access to it, revealing this in Okaz was more likely a warning than a bid to push Assad out. Like the Americans, the Saudis want Syria to break with Iran and Hezbollah--behavior change; they do not want to bring about regime change that might boomerang against them, particularly if it means Iran comes to Assad's defense by playing hardball in the oil-rich provinces of the kingdom where there is a sizable Shiite population.

However, at some point the situation may slip away from everyone. Serge Brammertz is in nobody's pocket and his conclusions in the Hariri investigation could shake the foundations of the Syrian regime in ways the Saudis would feel uncomfortable with. If that came about, would they try working a smooth transition in Syria away from Assad, or would they seek to keep him in power in a much-weakened condition?

And how would the U.S. respond? The administration may now have a useful partner against Syria, but how the Saudis behave could overly determine America's own approach toward Iran's leading Arab ally. This might be better than the bureaucratic compromise to which the U.S. is sticking today, but it still wouldn't mean much latitude to effectively address a threatening Syria.