Blair takes biggest gamble of his career
It dwarfs any domestic initiatives which have run into routine trouble, and even his intervention in Kosovo.
Now, as never before, he has a wide cross-section of both his party and the public hostile to his actions and suspicious of his motives.
Failure could leave a lasting scar on his premiership, obscuring the achievements at home and abroad he would prefer to be remembered for.
For the first time, there is even talk at Westminster that his leadership may be challenged.
Already, he has lost Leader of the Commons Robin Cook, who quit the Cabinet rather than back war, along with Home Office minister John Denham, junior health minister Lord Hunt of Kings Heath and a string of parliamentary private secretaries.
Mr Blair is staking everything on a campaign which he hopes will eventually be seen as both successful and just, but which opponents claim is morally dubious and could ignite the tinder box of Middle East politics without even successfully eradicating the weapons of mass destruction Britain and the US say Saddam possesses.
A swift victory with few civilian or allied military casualties may yet see his reputation recovered, but a controversial and drawn-out campaign with a mounting death toll could see him cast as the modern equivalent of Anthony Eden, the premier sunk by his disastrous intervention in Suez.
For the prime minister personally, as well as politically, the conflict is a watershed. He has spoken often of his anxiety at sending troops into battle and he discussed the morality of his own position in private audiences with both the Archbishop of Canterbury, Dr Rowan Williams, and Pope John Paul II at the Vatican.
Mr Blair, an Anglican, regularly attends mass with his Roman Catholic wife, Cherie, and their children who have been brought up in her faith.
His soul-searching on the morality of ordering death and destruction in this particular cause is bound to have been sincere and profound, and a campaign which goes off the rails could see the premier haunted by his own crisis of conscience. It is likely that once military action starts Mr Blair and his family will head for Southwark Cathedral to pray. He has said that the decision to order troops into battle is the hardest any premier can take, and he is agonisingly aware that he is sending some to certain death.
Mr Blair has tried time and again to confront his critics and win them round, whether through impassioned pleas in the House of Commons to his own sceptical MPs, or on TV with audiences deliberately chosen to be hostile. But, time and again, he has failed to turn the tide of opinion among the public and his party, and most church leaders have remained resolutely opposed to his strategy.
Instead of the dazzling diplomatic skills he has displayed in the past, his interventions during the crisis have looked lacklustre and even the White House began to run out of patience with his insistence on securing a second UN resolution against the odds.
The TV appearances supposed to show a man not afraid to tackle his critics and win them round have instead made him look isolated and vulnerable. He has sometimes appeared genuinely baffled as to why others cannot appreciate what he sees as the crystal clear logic of his argument.
Win or lose in the military campaign, many at Westminster believe his leadership has now passed a point of no return. That view was reflected in Clare Short's comments that Mr Blair has been "reckless" with his Government, his party and his reputation though she backed away from her threat to resign, acknowledging that he had no option but to launch military action.
The prime minister has been prepared to risk everything, and even some of those closest to him cannot understand why, or how, he allowed himself to get sucked into such a high-stakes poker game that eventually left him no dignified way of folding his cards and leaving the table. Even those within the Labour Party prepared to forgive him that, will never forget it, or view the premier in the same light again.
Surviving on four or five hours sleep a night at most, Mr Blair, who will be 50 in May, has also begun to look visibly weary as the strain takes its toll.
And he knows there will be many more sleepless nights to come before the war against Iraq is won.





