If the 45-year-old Obama were elected, he would become the nation's first African-American president.
"And that is why, in the shadow of the Old State Capitol, where Lincoln once called on a divided house to stand together, where common hopes and common dreams still live, I stand before you today to announce my candidacy for president of the United States of America."
Obama told the crowd he would tackle problems like poor schools, economic hardships and oil dependence, saying a "failure of leadership" is to blame for not meeting the nation's challenges. He also implored the crowd to demand that there be "universal health care in America by the end of the president's first term."
He called the Iraq war a "tragic mistake" and said, "It's time to admit that no amount of American lives can resolve the political disagreement that lies at the heart of someone else's civil war. That's why I have a plan that will bring our combat troops home by March of 2008.
"Letting the Iraqis know that we will not be there forever is our last, best hope to pressure the Sunni and Shia to come to the table and find peace," he said.
He also lauded what he called the founding fathers' "genius" in creating a system of government that can be changed. He cited examples throughout history -- from the American Revolution to the Civil War to the Great Depression -- in which Americans have demanded, and effected, change.
"We've done this before. Each and every time, a new generation has risen up and done what's needed to be done. Today we are called once more, and it is time for our generation to answer that call," he said.
The absence of sound policy is not what's holding the country back, he said.
