DENVER -- If you didn't know better, you might, for a minute, have thought that it was Al Gore who was here at Invesco Field to accept the Democratic Party's presidential nomination, so loud was the roar that greeted him when he took the stage.

The former vice president made the best of his defeat at the hands of George W. Bush eight years ago in making the case for Barack Obama.

"Take it from me, if [the 2000 presidential election] had ended differently, we would not be bogged down in Iraq, we would have pursued bin Laden until we captured him," Gore said. "We would not be facing a self-inflicted economic crisis ... We would not be showing contempt for the Constitution; we'd be protecting the rights of every American ... Today, we face essentially the same choice we faced in 2000 ... because John McCain ... is now openly endorsing the policies of the Bush-Cheney White House and promising to actually continue them."

Gore did get in a few lines that showed off his vastly underappreciated sense of humor, as he actually poked fun at himself and his loss. But the passion in his speech, and in the audience, cooled midway through the address; his discussions of global warming, though it's now his signature issue, just didn't pop.

But as he came to his conclusion, Gore picked it back up, especially as he talked about Obama. "There are times in the history of our nation when our very way of life depends upon awakening to the challenge of a present danger, shaking off complacency to rise, clear-eyed and alert, to the necessity of embracing change," Gore said, continuing:

A century and a half ago, when America faced our greatest trial, the end of one era gave way to the birth of another. The candidate who emerged victorious in that election is now regarded by most historians as our greatest president. Before he entered the White House, Abraham Lincoln's experience in elective office consisted of eight years in his state legislature ... and one term in Congress -- during which he showed the courage and wisdom to oppose the invasion of another country that was popular when it started but later condemned by history.

The experience Lincoln's supporters valued most in that race was his powerful ability to inspire hope in the future at a time of impasse. He was known chiefly as a clear thinker and a great orator ... 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.