Detroit ? Al Gore made his debut in the 2008 presidential campaign Monday night, encouraging voters to back Barack Obama because “take it from me, elections matter.”

The former vice president’s speech at the Joe Louis Arena was part endorsement and part blistering attack on the man who denied him the White House eight years ago.

“After eight years of incompetence, neglect and failure, we need change,” Gore said. “After eight years when our Constitution has been dishonored and disrespected, we need changes.”

In 2000, Gore won the popular vote but lost the disputed election to George W. Bush, who captured Florida and its electoral votes after a divided Supreme Court ended the re-count of ballots. Since then, Gore has made combatting global warming, his signature issue, and has been recognized worldwide for his effort – from an Academy Award to the Nobel Prize.