Six months ago, when media commentators were almost united in expecting a US attack on Iraq before Christmas, I argued on this page that the odds of a war in the year ahead were still only one in three. Six weeks ago, when President Saddam Hussein was mocking the UN and even the French seemed to be on the point of accepting the inevitability of conflict, I wrote that the confrontation in Iraq would probably continue until the autumn and might well end without a war.

Now Iraq has started destroying some of its forbidden weapons. Millions of demonstrators have turned Saddam into a global cult hero, a psycho-pathological aberration which shouldn’t surprise anyone on the 50th anniversary of Stalin’s death. And the UN Security Council, led by France, Germany and Russia, seems almost certain to demand that any military action be delayed until the autumn, precisely the timing I suggested last year.

Why, then, do I suddenly believe that war is, after all, inevitable — and that the fighting will begin by the end of the month?

The simplest answer is that George Bush has said so. Since the day this crisis started, the best way to judge what would happen next has been simply to listen to the White House, ignoring all speculative comments and interpretations from media pundits, international leaders or even subordinate US politicians such as Donald Rumsfeld, Dick Cheney and Colin Powell.

Until early last month, President Bush continued to emphasise “patience” and reiterate that war was his “last resort”, but in the past few weeks this rhetoric has totally changed. The White House line now is that the inspection process is essentially over, that time has run out, that Saddam has had his last chance. This change in American rhetoric may seem so obvious as to render all comment on it banal. But the causes and consequences of Washington’s sudden impatience are extremely important.

Let us begin with causes. There are two reasons why the possibility of a peaceful resolution — either through Saddam’s exile or his total capitulation to UN demands — has all but disappeared.

The more important has been the irresponsible behaviour of Germany and France. The self-indulgent posturing against America, which began at the Franco-German summit on January 14, encouraged Saddam’s hopes of splitting the West by denying Mr Bush the UN mandate which he was admirably seeking to give legal legitimacy to his own policies and diplomatic cover to his Middle Eastern allies.

Under these circumstances Saddam, who has built his whole life on self-delusion and wishful thinking, would not begin to contemplate exile or even co-operation with the UN. Thus the unexpected miscalculation of the French — who would normally have seen their national interest in raising the prestige of the UN Security Council and influencing US policy, rather than simply trying to thwart it — has been the main reason for abandoning earlier hopes that the Iraq crisis would be resolved without war.

Once again, the Franco-German obsession with “leading” Europe, this time through the constitutional convention, will result in thousands of lives being needlessly lost. The last time this happened was in Yugoslavia, when Germany triggered the civil war by cynically recognising Slovenia for domestic political reasons. France then backed this irresponsible position in exchange for Germany’s agreement to an early start for European monetary union.

But Washington, too, will be to blame if Iraq goes up in flames later this month. Even though the Franco-German sabotage undermined the chances of a rapid Iraqi capitulation, Saddam could still have been forced out without a fight later this year. Washington could have agreed to continue the UN inspections through the summer in exchange for cast-iron assurances of international support for an autumn war in the absence of total and demonstrable Iraqi disarmament.

Such a deal might still theoretically appear to be on the table, in the shape of the French and Russian proposals to give the inspectors four to six extra months. In practice, however, such a delay is now impossible.

The fact is that in the past few weeks Mr Bush has boxed himself into a corner by setting an effective deadline of the end of March. Whether he did this under pressure from the Pentagon hawks, in retaliation against the Franco-German provocations, or out of sheer stupidity is of secondary importance.

What matters is that America would now suffer a serious loss of international prestige if the attack on Iraq were delayed by more than a few weeks. Even more importantly, the world economy and financial markets, which have been led to expect an early resolution of the Iraq crisis, would quite possibly fall into another downturn far deeper than the one triggered by September 11.

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