Nobel laureate Al Gore on Thursday directly likened Barack Obama to the great US leader Abraham Lincoln, and blamed his former foe President George W Bush for "one calamity after another."
The former vice president said that had he emerged triumphant from the disputed 2000 election against Bush things would have been different, in a hard-hitting speech on the final day of the Democratic National Convention.
"Eight years ago, some said there was not much difference between the nominees of the two major parties and it didn't really matter who became president," Gore said.
"Our nation was enjoying peace and prosperity. Some assumed we would continue both, no matter the outcome.
"But here we all are in 2008, and I doubt anyone would argue now that election didn't matter."
Gore said that if he had been president, "We would not be bogged down in Iraq, we would have pursued bin Laden until we captured him.
"We would not be facing a self-inflicted economic crisis; we would be fighting for middle- income families."
And the famed global warming campaigner declared, "We would not be denying the climate crisis; we'd be solving it."
Gore compared Obama directly to president Lincoln, who like the Democratic nominee was once an Illinois state lawmaker, and is credited with saving the United States when the civil war threatened to tear it apart.
"The experience Lincoln's supporters valued most ... was his powerful ability to inspire hope in the future at a time of impasse.
"In 2008, once again, we find ourselves at the end of an era with a mandate from history to launch another new beginning.
"And once again, we have a candidate whose experience perfectly matches an extraordinary moment of transition."
Gore also slammed Republican candidate John McCain, who he said had ditched his maverick tendencies to embrace failed Republican policies.
"Hey, I believe in recycling, but that's ridiculous," Gore said, adding "it's time for a change."
"If you like the Bush-Cheney approach, John McCain's your man. If you want change, then vote for Barack Obama and Joe Biden."