(CNN) - Former Vice President Al Gore endorsed Democratic presidential candidate Barack Obama on Monday, urging Americans to reject what he called the Bush administration's legacy of "incompetence, negligence and failure."
"Americans simply cannot afford to continue the policies of the last eight years for another four," Gore, the party's 2000 presidential nominee, told Obama supporters at a rally in Detroit, Michigan.
Perceived as a senior statesman in the Democratic party, Gore brings a certain force to Obama's campaign, political analysts have said.
Monday marked Gore's debut in the 2008 election; he had not weighed in while Obama was still battling Sen. Hillary Clinton.
Amid thousands of cheering supporters, Gore began by addressing head-on the criticism that Obama doesn't have enough experience to lead the nation.
The former vice president turned Nobel Prize winner playfully said he recalled one Republican nominee wondering out loud whether his Democratic rival for president was "naive and inexperienced."
"And yet another said the United States cannot afford to risk the future of the free world with inexperience and immaturity in the White House," said Gore. "Who were they talking about? Every single one of those quotes came from the campaign of 1960, when the the Republicans attacked John Fitzgerald Kennedy for allegedly lacking the age and experience necessary to be president."