Obama wades into 2008 White House race

Obama said he was struck by a hunger around the country for "a different kind of politics" and that decisions in Washington over the last six years of Republican leadership have put the country "in a precarious place."

"Our continued dependence on oil has put our security and our very planet at risk. And we're still mired in a tragic and costly war that should have never been waged," said Obama, an early opponent of the invasion of Iraq.

"But challenging as they are, it's not the magnitude of our problems that concerns me the most. It's the smallness of our politics," he said in his statement.

Obama's quick rise has been fueled in part by a smooth campaign style and unusual personal history. The son of a white Kansas-born mother and a black Kenyan father, the Harvard Law School graduate and little-known state legislator in Illinois won the U.S. Senate seat in 2004 against a stand-in opponent.

He has written two best-selling books and won a Grammy Award for his recording of his autobiography.

Republican Rep. Tom Tancredo of Colorado, a leading foe of illegal immigration, also formed a presidential exploratory committee on Tuesday. He became the eighth Republican candidate in the field.

The other Democrats in the race are 2004 vice presidential nominee John Edwards, former Iowa Gov. Tom Vilsack, Ohio Rep. Dennis Kucinich and Connecticut Sen. Chris Dodd. More are expected to join the race soon.

"Voters across our country are going to hear a real debate about how to put the Bush years behind us and get America moving in the right direction," Vilsack said.

Obama said he would spend the next few weeks listening to voters and learning about "the role that a presidential campaign might play in bringing our country together."