US Senator Barack Obama launched a presidential campaign that could make him the first black to occupy the White House, and he immediately tried to turn his political inexperience into an asset with voters seeking change. The freshman Illinois senator - and top contender for the Democratic nomination - said Tuesday the past six years have left the country in a precarious place, and he promoted himself as the standard-bearer for a new kind of politics. "Our leaders in Washington seem incapable of working together in a practical, commonsense way," Obama said in a video posted on his Web site. "Politics has become so bitter and partisan, so gummed up by money and influence, that we can't tackle the big problems that demand solutions. And that's what we have to change first." Obama, whose father was Kenyan, filed paperwork forming a presidential exploratory committee that allows him to raise money and put together a campaign structure. He is expected to announce his candidacy on Feb. 10 in Springfield, Illinois, where he can tout his experience in the state legislature and tap into the legacy of hometown hero, President Abraham Lincoln.