It was to be expected that the 84,000 Democratic partisans would respond with boundless enthusiasm to Barack Obama's speech framing the 67-day campaign against Republican presidential candidate John McCain.

Far less certain was how the media opinion-moulders in the United States would judge Senator Obama's performance in Denver on Thursday night.

After weeks of stoking doubts over Mr Obama's strategy and suitability for the world's highest office, the most influential commentators are nearly unanimous in rating his speech highly effective - both politically and substantively.

All paid homage to the historic breakthrough represented by an African-American's unprecedented journey to the very threshold of the Oval Office.

Note was made of how far black Americans have progressed politically in the 45 years - to the day - since the Rev Martin Luther King Jnr delivered his epochal "I have a dream" speech in Washington.

Senator Obama enters the final round of the presidential race with a strong prospect of success. But the undercurrents of racism still coursing through white America ensure that victory will not come easily to Mr Obama - and may not come at all.

Much to admire

The New York Times and Washington Post - both favourably disposed toward Mr Obama but also worried about his ability to win the White House - offered strong endorsements on Friday.

Even some commentators with generally conservative views found much to admire in Mr Obama's remarks.

David Gergen, a CNN pundit who advised three Republican presidents, called the speech "a political masterpiece."

The Wall Street Journal, a reliably fierce scourge of even slightly left-of-centre politicians, conceded in an editorial on Friday that Mr Obama's "political and oratorical gifts are formidable, as he showed during the primaries and last night.

His campaign skills - in fundraising and staff organisation - deserve more than a nod for defeating the Clinton juggernaut in the primaries."

USA Today, the nation's largest-circulation daily, praised Mr Obama's "newfound aggressiveness" in responding to Republican adverts that have dented his image.