Richardson launched his bid in California, the state with the largest Hispanic population and a pivotal player in the November 2008 election thanks to an early February primary.
He zeroed in on issues considered important by California voters, like immigration and the environment, in addition to Iraq, healthcare reform and aiding the middle class.
''The United States faces huge challenges both here and abroad, and I'm running for president because this nation needs a leader with a proven track record, an ability to bring people together to tackle our problems,'' he said.
Richardson, 59, has been campaigning for months but has largely only registered in the single digits in national opinion polls, trailing front-runners Senators Hillary Rodham Clinton of New York and Barack Obama of Illinois and former Senator John Edwards of North Carolina.
''Some are rock stars,'' said Richardson, referring to his fellow candidates. ''I am not. I won't have their money, but I will have the voters and the grass-roots campaign.'' Like other Democrats, Richardson has blasted the Bush administration for its handling of the Iraq war and at the party's first debate last month he called for withdrawing all US troops by the end of this year.
''I would leave no troops behind in Iraq,'' he said.
During President Bill Clinton's administration, Richardson served as the US ambassador to the United Nations and energy secretary, in which he gained a reputation as a skilled negotiator. He also was a member of Congress for 14 years.
''As president I will make sure that the American people are led with the following ideas: diplomacy and negotiation first, diplomacy second and diplomacy third,'' he said.
CRITICIZES IMMIGRATION BILL Flanked by Los Angeles area Latino leaders, Richardson switched comfortably between English and Spanish and spoke of a bipartisan bill on immigration reform in debate in the Senate this week.
Richardson said the bill was a step in the right direction because it gives some 12 million undocumented foreign workers a chance at legal status, but it was wrong by not guaranteeing that families could stay together.
''We should not support any measure that divides families,'' said Richardson, who was born in California to an American father and a Mexican mother.
Richardson used the California stage to play up his credentials on fighting global warming in a state that is widely considered the most aggressive in cutting greenhouse gas emissions with a 2006 law signed by Republican Gov Arnold Schwarzenegger.
''We also need a president who is not dismissive of energy independence and global warming,'' Richardson said. ''This is no longer a choice, it is a moral imperative for a planet and a matter of survival for our country.'' His plan, lauded by environmentalists, has goals similar to California.
''Within 12 years, my plan would reduce greenhouse emissions by 20 percent, lower demand for oil by 50 per cent and push fuel economy standards to 50 miles per gallon,'' Richardson said.
REUTERS KK PM2000