There would be, for me, something unseemly in barking at the wheels of our military pantechnicon now that it is rolling, so I shall pipe down on the war itself. I have offered my opinion and it has not changed. There are some, now, for whom war becomes riveting simply as spectator sport and who feel impatient at any discussion of its purpose. They need not bother to read on.

But on this page seven weeks ago I also said that honest doubters should look beyond the conflict. What, I asked, if an attack proved straightforward and relatively unbloody? What if victory brought cheering crowds and a better Iraq? At the end of January I suggested that was my hunch. I repeat it now.

And move on, as did Tim Hames on this page on Monday: “Why this war is going to draw a line in the sand.” Looking to the consequences of war, Mr Hames made the case against us doubters. His argument was clear and strong. He grouped doubts about the invasion under three separate heads: “Why must it start?”, “How will it end?” and “Where will it stop?”.

Let us agree that, for the moment, argument about why the war should start is pointless. It has started. And let me repeat my guess that the answer to “How will it end?” will be “in easy victory”. Which brings us to “Where will it stop?”. This question (as Hames observes) remains current. Indeed, the easier the victory the more current the question.

Or so (at least) most Conservative doubters on this war have felt. The list includes more distinguished observers than me: at least three former Cabinet ministers, Kenneth Clarke, David Howell and Douglas Hogg; as well as Andrew Tyrie, the MP for Chichester who has just published a Bow Group and Foreign Policy Centre pamphlet on the subject.

Tim Hames believes he can answer our doubts. This is his concluding paragraph: “The most significant effect of Saddam’s demise will be to persuade others that weapons of mass destruction are not a market in which they should set up in business. In other words, regime change will act as a deterrent, pre-emption will reinforce containment. Iraq is the exception that will establish the post-September 11 rules. The most plausible answer to ‘Where will it stop?’ is, therefore, not ‘Pyongyang’, ‘Tehran’ or ‘Timbuktu’, but ‘Baghdad’.”

Mr Hames would not be so crude as to put it like this, but he is arguing that a raised fist, if big enough and raised high enough, has only to smash in one set of teeth for all further use of force to become unnecessary. Just the sight of the fist will do the trick.

This is to elevate the “Shock-and-Awe” doctrine from the battlefield to the permanent arena of international relations. One tremendous bang — and further opposition ceases. It’s a seductive thought.

It is also mistaken. There are two reasons why US victory will not end the argument. The first is that, even if Shock and Awe could bring immediate peace, there are reasons why Washington will prove unable permanently to maintain the shockingness and the awesomeness at the required level. America’s fist is not big enough and will not be raised high enough and steady enough for long enough.

My second doubt goes to the theory itself. A big raised fist brandished by a power which remains subject to civilised limits does not, I believe, guarantee order; but instead spawns new forms of insubordination.

Let us examine first the hope that America will henceforward seem permanently invincible. So fashionable has it become to repeat that there is now only one great power in the world, that we are in danger of overlooking the real strength of some of the smaller powers, particularly should they act in groups. America is bigger than any rival, but does not dwarf them.

Andrew Tyrie puts it like this: “Preponderant though the US is, she is not strong enough to impose her will on everyone. It would be a delusion to believe that the US, even with assistance from much of the West, has either the military capacity or the political will to make Western values the values of the whole globe.”

There are two sources to America’s power: money and weapons. US economic preponderance should not be exaggerated. Other economies are growing fast. America can bribe, of course — though the limits to that may have been indicated recently by (for instance) Turkey and the non-permanent members of the UN Security Council. It can also blackmail, though sanctions and tariff barriers are a double-edged sword. But it is not straightforward, particularly for a vigorous democracy, to translate economic strength into a practical means for the daily enforcement of political will. We British, too, enjoyed a measure of economic predominance in the 19th century but it did not last long and was never unchallenged.

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