George Bush has taken only seven days to learn for himself the brutal, unyielding realities of the Middle East. A week ago in the Jordanian resort of Aqaba, a smiling President, flanked by the Israeli and Palestinian Prime Ministers, emerged from a summit to launch his road-map to peace.
That road-map now may not quite be in shreds. But after the blows of Israel's attempt to assassinate a leader of the Hamas militant group, and yesterday's devastating suicide bombing in Jerusalem, followed by deadly Israeli retaliatory strikes in Gaza, the vision of a comprehensive Middle East settlement by the end of 2005 has never looked so remote.
It misses the point to talk of the tragic events of the past 48 hours as a "failure" of Mr Bush's, one that has cost precious political capital. No US president will ever be blamed for trying to secure peace. Indeed, until the launch of the road-map in April, one of the main criticisms of the administration was that it had not made enough effort to resolve the Middle East crisis.
If any assumption has perished amid the latest bloodletting, it is that words alone suffice. The Bush style has been to lay down goals (most strikingly the creation of a proper Palestinian state) and leave the tricky details to the others. Indulging his taste for imagery taken from Westerns, the President spoke of his role as "riding herd". He would whip the two parties along, to make sure they honoured the timetable, and that would be it.
The necessary conditions, moreover, seemed present. A new Palestinian Prime Minister of whom Washington approved, Abu Mazen, was in place. The elimination of Saddam Hussein's regime, long urged by Israel, meant that the Jewish state "owed" Mr Bush.
But in the Middle East nothing is ever straightforward. Washington might pretend that the Palestinian leader Yasser Arafat had been marginalised. But it is Abu Mazen who risks marginalisation, unless he can tame the terrorists. Israel too has signalled that, road-map or no road-map, it will not shrink from violence.
Not surprisingly, some look to the internationalisation of the peace enforcement effort. John Warner, the influential chairman of the Senate armed services committee, called for Nato to be sent in. The US alone would not be a credible broker, he argued, but Israelis and Palestinians alone have utterly lost control of events. On that, at least, everyone could agree yesterday.