London ? The war in Iraq has not set back the cause of using force to overthrow murderous dictators in the Middle East or elsewhere, says Tony Blair, one of the progenitors of the bold concept of humanitarian intervention.

But the British prime minister indicates a deepening awareness that war is an unpredictable, blunt instrument of change. His words suggest that he will not by any means pronounce the meal of intervention a failure. But his appetite has been slaked.

Blair’s ideas on humanitarian intervention — which the semanticists at the United Nations now call the international “duty to protect” innocent civilians from massive human rights abuses committed by their own governments — have over the years influenced my own thinking on the subject.

So in a conversation last week I inquired about the effect of the Iraq War on three issues: the Middle East, which has recently been jolted by a surge of positive political change; Blair’s impending re-election bid; and the political framework that nations construct for going to war.

Facing a higher threshold at home than did President Bush on the need to clearly establish legal grounds for invading Iraq, Blair’s New Labor government stridently emphasized Iraqi violations of U.N. resolutions on weapons of mass destruction and the threat those weapons allegedly presented. Humanitarian intervention to remove Saddam Hussein was subordinated to the “WMD” argument in London and Washington.

In retrospect, I regret that those of us who had long favored regime change in Iraq to prevent renewed genocide and regional aggression did not do enough to clarify and separate these causes in the American debate. Blair seems unrepentant on this point:

“As a matter of law, the breach of United Nations resolutions was critical,” Blair said. “But sometimes there is a false distinction in this. As I said in February 2003 … the nature of a regime is immensely important in determining how serious a view we should take of the breach of U.N. resolutions. WMD issues with a benign regime is a completely different manner of problem than WMD issues with a regime that is thoroughly evil and wicked, as this one was.

“I confess I have always believed that it is absurd to say in international law that a state can do whatever it wants with its own citizens. Surely if we believe in human dignity and human rights, that extends to whatever country a person happens to be in.”

The failure to find the weapons that American, British, French, German, Russian and other intelligence services and U.N. inspectors believed were still in Iraq — in one form or another — has raised serious doubts about the motives of Bush and Blair in going to war. Isn’t this a setback for public confidence in intervention, humanitarian and otherwise?

“It should not be,” Blair replied. “It would have been a really serious setback if we had replaced one strongman regime with another. That would have been a disaster. That is why the January election was vital. I think that the elections in Afghanistan and Iraq have opened a lot of eyes. … It is clear that helping people onto the path of democracy is part of our security.”

During the Kosovo campaign six years ago, as he was pushing a reluctant Bill Clinton to prepare to use NATO ground forces, Blair complained to me about stereotypes of leaders from the political left being unwilling or unable to fight for what they believed in. Hasn’t his own stubborn, politically costly engagement in Iraq disproved that stereotype, and was that an unalloyed blessing for him?

Blair glanced away in rueful thought before responding. “There are very few blessings” unalloyed or otherwise for him on Iraq, he offered.

He won’t talk about the next British election, which he will soon announce for May 5. But it is already clear that his electoral situation is the reverse of the one Bush faced in November.

Bush overcame the challenges to his credibility on Iraq to win re-election, even though he did not score well in exit polls on his management of the conflict. In his campaign, Blair will emphasize his broadly acknowledged competence and a booming economy. Winning back trust will be a secondary task, probably beyond reach. Says one Blair intimate: “Iraq is a ball and chain for us, but not a salient campaign issue.”

As a practical politician, Blair looks first to results. Call it what you want, he seems to say, but recognize that because of the Iraq invasion “there is now an opportunity of developing a coherent program of change for the entire Middle East” that is at long last moving forward.

— Jim Hoagland is a columnist for Washington Post Writers Group.