But as a canny head teacher said to me before it started, the Iraq war of 2003 is the first in history whose moral virtue will be judged on its outcomes, not on the motives for starting it.
And one of its next outcomes needs to be a spot more regime change. A month ago, I said here that Tony Blair's courage on Iraq would put him in a strong position to convince Bush to put the frighteners on Israel's unpleasant, dangerous prime minister.
We know Blair wants to. Now he must, very quickly indeed, and achieve a fantastic result. One that will explain how the war was just the start of a process of civilising the Middle East. This truly is Blair's biggest challenge.
The stubborn, paranoid, frightened, aggressive Israelis, who have little interest in what we in Britain think about them, are not even the first obstacle to overcome.
Nor are the Palestinians, whose ability to knock in spectacular own goals just when they're about to score, would be comical were it not so tragic.
The real problem is George W Bush and his reliance on Christian fundamentalists at home. The famous "Jewish lobby" is neither here nor there to Bush. Jews mostly vote Democrat. Loony Bible-bashers, on the other hand, see Ariel Sharon's right-wing government as the fellow nutcases most likely to deliver the second coming of Jesus Christ. I kid you not.
They love Sharon, and they support the troublemaking Jewish fundamentalist settlers on Arab lands. So first Bush has to be prepared to ignore the illiterate, churchy rabble in Texas and the south.
He has to get on the phone to Sharon and stay on it. He must explain that Saddam, who bankrolled the suicide bombers, has gone. That Iraq, the worst threat to Israel, is now neutered. So Sharon must now seize the chance for peace. Or else.
We can't persuade him by force. But Bush can make things impossible for Sharon, to force him out democratically. By promising no more arms for Israel. No more aid until they stop smashing Gaza and bulldoze their own madmen instead.