"Bush's address was clearly the most assured and confident performance he has delivered ..."

On the brink of war, the pre-eminent political task usually facing a US president is to rally his country's support for military action. As his speech to Congress yesterday demonstrated, George W. Bush faces a very different political test: defining a sustainable and achievable goal for the military action that most Americans already support.

His greatest challenge may be less rallying his country to arms than restraining its expectations of what military action can achieve, especially in the short run.

Bush's address was clearly the most assured and confident performance he has delivered on a national stage; for many Americans who have doubted his capacity, and even his legitimacy, it may have been the first time they saw him filling the presidency.

The overwhelming public support for military retaliation has placed Bush in a fundamentally different position than his two predecessors, each of whom also placed service personnel in harm's way.

In similar speeches to the nation - George Bush senior during the Gulf War and Bill Clinton during the NATO campaign in Kosovo - a president faced the burden of convincing sceptical Americans that those distant lands were worth the risk of American lives.

But with support for force already assured, Bush had several other aims in his address yesterday: reassuring the country that his administration is taking all reasonable precautions to prevent another attack; steeling US troops for the conflict ahead; blaming Osama bin Laden; and issuing a series of pointed ultimatums to the Taliban.

Above all, Bush's challenge was to define very clearly what victory means. His speech still demonstrated how difficult a task that could be in a war without conventional battlefields, familiar military targets or even a generally agreed-upon definition of success.

Bush displayed resolve without appearing rash, and emphasised tolerance (for Arab Americans and Muslim Americans) as much as vigilance.

The faintest note in Bush's daily dialogue with the public has been in explaining exactly what this new kind of war will entail. That's hardly surprising: policymakers across the Western world are struggling to define a meaningful military campaign against an enemy as elusive as global terrorism. The September 11 attack was an event so unexpected that it has propelled virtually all Americans - from the senior policymakers down - into uncharted territory.

The President and his aides have devoted much of their public communication to explaining why the American response won't look like a conventional war. It will not, for instance, produce the quick and decisive results that at times made the Gulf War look like a video game.

The effort to prepare America for an ambiguous and amorphous conflict continued in yesterday's speech. Bush went out of his way to stress that the coming struggle will look neither like the Gulf War - "with a decisive liberation of territory and a swift conclusion" - nor the campaign in Kosovo, with its casualty-free vision of an antiseptic war fought only from fighter jets at 20,000 feet.

Americans, he suggested, may have to accept the pain of casualties without the catharsis of dramatic, telegenic victories over massed armies or fixed targets.

Already substantial, the American public's confidence in the President's handling of the crisis is likely to grow even greater after last night's speech - which, coming exactly eight months after his inauguration, may be the first Bush address to earn a place in the history books. There was no trace of the tongue-tied word-mangler so often lampooned.

But Bush will face a continuing challenge of maintaining support in an unconventional conflict that is likely to test Americans in profound ways. Bush's words committed him, and his nation, to a goal that may be no easier to fulfil than earlier government "wars" to eliminate drugs or poverty.

LOS ANGELES TIMES