BEIRUT -- Iran 2, the United States 0.

Last year in the Gaza Strip, now in Lebanon, Tehran's proxy armies rapidly defeated the weak and isolated friends of the West.

The latest rout came on the streets of Beirut yesterday, where Iranian-backed Hezbollah fighters occupied much of Sunni Muslim West Beirut, turf that once belonged to America's friends in Lebanon, Saad Hariri, Walid Jumblatt and Prime Minister Fouad Siniora.

For months, pundits had speculated that Lebanon was on the verge of another civil war, with some speculating that it could be nearly as prolonged and bloody as the last conflict, which lasted from 1975 to 1990 and left approximately 100,000 people dead.

But by early yesterday morning, it became abundantly clear that Mr. Hariri's Future Movement, which had been so hopefully named by his peacemaker father before his still-unsolved assassination in 2005, was no match for Hezbollah's military might.

The United States and its Sunni Muslim allies, primarily the tiny but affluent United Arab Emirates, had funnelled money and weapons to Mr. Hariri's men in anticipation of this conflict, apparently to no avail. By nightfall, all the White House could do was condemn Hezbollah's aggression and express its “unswerving support” for Mr. Siniora's humiliated government. The comparisons to Gaza — where Iranian-backed Hamas routed the Western-supported Fatah movement of Palestinian president Mahmoud Abbas in six days, seizing complete control of the coastal strip — were obvious and inescapable.

There, too, the United States invested heavily in a secular party that fit U.S. President George W. Bush's dream of a moderate, pro-Western Middle East. As in Lebanon, they proved great at shaking hands with Condoleezza Rice, less able when it came to armed combat against militant Islamists armed and equipped by Tehran.

Though the crisis over Iran's nuclear program has yet to come to a head, the war between Tehran and Washington is already very much under way. It has been since the day the United States toppled Saddam Hussein and made it clear Iran could easily be next.

Motivated in part by that fear, in part by a desire to supplant the United States as the hegemonic power in the Middle East, Iran has ably joined the geopolitical battle, funding chaos and undermining the American vision of a “new Middle East” across the board.

Iranian-backed Shia militias have helped ensure that Iraq would never turn into the pro-Western democracy the neo-conservatives once dreamed it could be. Hamas rockets have made sure that Mr. Bush's efforts to promote Israeli-Palestinian peace have been largely a road map to nowhere. And now Hezbollah has demolished the last traces of Lebanon's pro-Western Cedar Revolution of three years ago.

Throughout this cold war with Iran, Washington has consistently misunderstood its hand, and how angry the “Arab Street” was over the invasion of Iraq and the decades of unconditional support the United States has lent Israel. And by stubbornly isolating Syria and Hamas – the former a secular dictatorship uncomfortable among its Islamist allies, the latter a Sunni militant group instinctively suspicious of Shia Iran – Mr. Bush pushed them further into Tehran's embrace, strengthening the rejectionist axis that Iranian President Mahmoud Ahmedinejad now leads.

His administration also badly underestimated their enemy's strength, and has been astonishingly slow to learn the cutthroat rules of the Middle East.

In Lebanon, the cards played out like this: If and when the nuclear crisis boils over into military conflict, Iran needs Hezbollah to be armed and ready to strike America's top ally in the region, Israel. So when Mr. Siniora's government declared this week that it would dismantle Hezbollah's secret communications grid, a fibre-optic network that leader Hassan Nasrallah declared to be a critical part of his group's arsenal, the gloves came off.

Iran decided it couldn't allow Washington to take away one of its best weapons on the eve of a potential fight. So its proxy, Hezbollah, carried out what appears to have been a long-prepared plan for seizing control of West Beirut.

Last year, Jordan's King Abdullah made international headlines when he warned that the Middle East would soon face three separate conflicts, in Iraq – where Iranian-backed Shia militants are at war with both Sunni fighters and the occupying U.S. army – as well as Palestine and Lebanon.

King Abdullah erred only in describing the three as separate fights rather than what they are: fronts in the same war. And none of them are going terribly well for the old hegemon right now.