The crisis over the investigation into Rafik Al-Hariri's assassination has once more made Syria a foe in Washington, writes Graham Usher In a week when Barack Obama lost much of Congress the main preoccupation of his foreign policy officials was not Afghanistan or Yemen or even the corpse-like Middle East "peace process". It was Lebanon. "The most critical issue of international peace and security today," said United Nations Special Envoy to the country, Terje Rod-Larsen, on 28 October. He had just addressed a closed UN Security Council (UNSC) session on the crisis caused by its investigation into the 2005 murder of former Lebanese prime minister Rafik Al-Hariri. Late this year or early next, the UN's Special Tribunal on Lebanon (STL) is expected to indict members of Hizbullah, the Lebanese resistance movement. Hizbullah has cast the STL as an "American and Israeli plot". On 28 October its chief, Hassan Nasrallah, moved the sights closer to home: any Lebanese collaboration with the STL would be "equal to an attack on the resistance", he said. The UNSC set up the STL in 2007 with the support of the current Lebanese Prime Minister Saad Hariri. His government -- with majority parliamentary support -- has pledged to defray half its costs and enforce its judgements. The US says it's "vitally important" for Lebanon's future. The battle lines could not be clearer. Yet it wasn't only Hizbullah or even its patron Iran that the US denounced at the UNSC for once more bringing Lebanon to the edge. "Syria especially has displayed flagrant disregard for the sovereignty, territorial integrity, unity and political independence of Lebanon," said US UN Ambassador Susan Rice. It "continues to provide increasingly sophisticated weapons to Lebanese militias, including Hizbullah... the most significant and heavily armed Lebanese militia". Syria denies the charge. Hizbullah weaves a web of "strategic ambiguity" over its arsenal, and says nothing. And Lebanese government officials admit only the "possibility" that arms are smuggled across the "porous" Syria-Lebanon border. But whatever the provenance, Lebanon is becoming re-armed, said Larsen, and "these weapons are not coming from the moon." Rice's demarche seems to draw a close on Barack Obama's tentative "engagement" with Damascus. Pursued ostensibly to woo back Syria to a "comprehensive" peace process with Israel, it was more about prying Syria away from Iran as well as from Hizbullah and Hamas, deemed Iranian proxies by Washington. For 18 months Obama dispatched emissaries to President Bashar Al-Assad. He promised a new US ambassador in Damascus after the exit of the last one in 2005 amid charges that Syria was behind Al-Hariri's assassination. And, on 30 July, he blessed a trip to Lebanon by Al-Assad and Saudi Arabia's King Abdullah to staunch the growing crisis over the STL. The trade-off was clear: renewed acceptance of Syria's dominant role in Lebanon so long as it checked Hizbullah on the tribunal and kept Iran out of Lebanon's domestic politics. Syria did neither. It endorsed Hizbullah's claim that the STL was an Israel front, arguing that it should be replaced by a Lebanese court. In October, a Syrian judge issued 33 arrest warrants against Lebanese and other officials for giving "false testimony" to the UN probe, including close allies of Saad Al-Hariri. The 33 had reportedly implicated Syria in his father's murder. Finally, Syria gave the nod to last month's trip to Lebanon by Iranian President Mahmoud Ahmadinejad, an act that graphically showed the depth of Iranian influence in Lebanon, particularly among its majority Shia sect. The message was lost on no one. "The lesson we should learn from Ahmadinejad's visit is that Iran is on the northern border of Israel," said Israel's National Infrastructure Minister Uzi Landau. Washington called the visit a "provocation", and drew the same conclusion. In Beirut, Ahmadinejad echoed Hizbullah and Syria that Israel was behind Al-Hariri's assassination, saying "friends are being framed" for the murder of "a friend and patriotic man". What is behind this assault on the STL? Many observers believe Hizbullah are asking Saad Al-Hariri to do the impossible. He has already recanted an earlier charge that the Syrian regime killed his father. He reportedly offered a deal to Nasrallah where, although Hizbullah members would be indicted by the STL, they would be tagged "rogue elements" with no move against them or smear on the movement. But Al-Hariri cannot disavow an international investigation into his father's killers that he himself called for, that most of his Sunni community wants and with which his government has vowed to comply. For Hizbullah, Syria and Iran to demand that Al-Hariri disown the STL is to demand that he and his bloc leave the government. This at least is how it is read from Washington. "We understand that certain actors within and outside Lebanon -- including Syria, Hizbullah and Iran -- may believe that escalating sectarian tensions will help them assert their own authority over Lebanon. However, these actors serve only to destabilise Lebanon and the region," warned Rice. The message is pretty clear: Washington will not accept any ousting of Al-Hariri's National Unity government, nor any tinkering with an "independent" STL. For Israel any replacement by the Hariri government with an avowedly pro-Syrian one would be another step towards war. Is there an exit? In theory, having established the STL, the UNSC could dissolve it. But given the importance Washington now attaches to the probe few think that will happen. Others look again to Syria and Saudi Arabia to broker a compromise. Still others hope a tribunal endlessly delayed can mean a judgement denied. But Hizbullah and Syria's insistence on disavowal suggests their fear that, without closure of some sort, Al-Hariri's ghost will continue to haunt them and Lebanon. Old Lebanese hands say their country only stops being at war as long as no one party seeks to be victor or vanquished. Hizbullah, Syria and Iran seem to seek both.