To be more precise, the “elephant” has not been the war itself, but the Prime Minister’s abandonment of Britain’s national interests in his blind obedience to President Bush. Yet the strangest feature of the Labour Party’s catharsis last week is that it wasn’t cathartic at all. In all the agonies of last week, nobody mentioned the trauma that was the root cause — that almost all Labour activists and most voters have come to detest and distrust Mr Blair because of his support for US foreign policy, not only in Iraq, but also in Lebanon, Israel and Iran.

If this is true — and it seems self-evident from the polls, not to mention the anti-Blair placards at the TUC — then the debate that the Labour Party needs to have in the months ahead is not over hospitals or schools or pensions. It is about foreign policy, the US and Iraq. If Gordon Brown sticks to Mr Blair’s foreign policies, he will lose the next election. If he can present a credible alternative, then he could easily win, whatever his personal quirks or psychological flaws.

Among all the clichéd parallels between the Blair endgame and the removal of Margaret Thatcher — “he who wields the dagger” and so on — the most relevant lesson seems to have been entirely missed. The reason for Mrs Thatcher’s removal was not her arrogance or her “madness”. It was her unpopularity. This, in turn, had less to do with the poll tax or rows over Europe than it did with the hardship that the Thatcher Government had inflicted on voters (especially working-class Tory voters) by jacking up mortgage rates to 15 per cent in 1989. These sky-high interest rates were necessitated first by Nigel Lawson’s policy of “shadowing” the Deutschmark and then by John Major’s decision to join the European exchange rate mechanism.

Mr Major’s failure as a prime minister was down to a fatal policy mistake: his decision to keep Britain in the ERM regardless of cost. In doing this, the Tories effectively handed control of monetary policy to the Bundesbank, just as Mr Blair has subordinated foreign policy to the White House. Once it became apparent on Black Wednesday that this humiliating loss of control over economic policy had never been in Britain’s national interest, Mr Major was effectively finished.

The same thing happened to Mr Blair this summer as a result of the “Yo Blair” episode, the airline bomb scares and the Lebanon war. And with hindsight there is another parallel that Mr Brown may find intriguing with the ERM debacle. Like US foreign policy today, German economic policy in the 1990s was run by a pair of arrogant but incompetent ideologues. Theo Waigel and Helmut Schlesinger, the German Finance Minister and Bundesbank President, were to economics what Donald Rumsfeld and Dick Cheney are to the art of war. The German leaders of the early 1990s managed to turn their once-great economy into the sick man of Europe, just as Mr Rumsfeld and Mr Cheney have reduced America from a military superpower to a paper tiger.

But does Mr Brown have any real choices in foreign policy? Much as it dislikes President Bush and his cohorts, the Foreign Office will doubtless tell the new Prime Minister that Britain has no alternative — when the chips are down, we must always side with the US. “There is no alternative” is of course a familiar slogan from the days of John Major, and it is as stupid today as it was then. There will, in fact, be plenty of alternatives.

President Bush may have defined the world in Manichean terms — “either you’re for us or against us” — but Britain does not have to accept this division. It is perfectly possible, as David Cameron pointed out this week in a wise foreign policy speech, to be pro-American but against the Iraq war, especially as it has been conducted. Indeed, the biggest service that Britain could have done for America in the past three years would have been to criticise the conduct of this war by the Pentagon, first in private, and then in public.

To my mind, Mr Blair’s truly unforgivable crime was not the invasion of Iraq (which I initially supported, believing that the US had a coherent plan to stabilise the country after the Saddam regime was toppled). No, Mr Blair’s crime was to continue backing President Bush after it became obvious that his policies were criminally negligent, politically cynical and doomed to failure.

Mr Blair was the one man in the world who could have forced President Bush to back Colin Powell, sack Donald Rumsfeld, close down Abu Ghraib and Guantanamo and launch a serious drive for Palestinian statehood. In the months before the 2004 presidential election, when President Bush was behind in the polls and desperate for international support for the Iraq adventure, Mr Blair could have laid down all these conditions — and more — for his continuing participation in Iraq. He did not even try.

The next prime minister will have to do better. There are many constructive ways to do this. He could withdraw troops from Iraq and simultaneously double the Army’s strength in Afghanistan, where there is still some hope of success, especially if the West temporarily abandons its futile effort to destroy the opium economy at the same time as fighting the Taleban. He could redeploy British troops to Sudan, where they could save hundreds of thousands of lives. He could urge Washington to talk directly with Iran and campaign in Europe for a lifting of sanctions against the Palestinian Authority.

The list could go on and on, but all these ideas have one point in common: what Britain needs is a new foreign policy that is not anti-American, nor even anti-Bush, but one that is clearly opposed to President Bush’s blunders. If Gordon Brown cannot provide this, David Cameron soon will.

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