COLUMBIA , South Carolina ( CNN ) -- Oprah Winfrey delivered her `` favorite '' candidate in the presidential race something his campaign hoped for Sunday : the largest crowd yet of any event in the race to '08 , according to the Obama campaign . Oprah campaigned with Obama this weekend in Iowa , New Hampshire and South Carolina . Although exact figures were not immediately available , campaign officials estimated more than 30,000 people packed into Columbia , South Carolina 's Williams-Brice stadium to hear the talk-show queen explain why she believes Obama is the man with the `` vision '' for America . `` Dr. King dreamed the dream . We get to vote that dream into reality by supporting a man who knows not just who we are but who we can be , '' she told the crowd . South Carolina is one of the first states in the nation to hold its presidential primary , making it key to the success of any presidential candidate . Winfrey gave a similar speech Saturday in the first stop of a two-day , three-state tour with her fellow Chicagoan . She discussed on Sunday stepping out of her `` comfort zone '' by entering the political scene on behalf of a candidate , and praised Obama 's `` ear for eloquence and tongue for unvarnished truth . We need politicians to tell the truth and be the truth . '' Watch what issues are important to Iowans » . She also said Obama would bring `` a sense of statesmanship '' to the White House . Watch Winfrey endorse Obama » . After extensive thank-yous to his wife Michelle and to Winfrey -- and acknowledging that the crowd was largely there to see Winfrey , not him -- Obama launched into his stump speech . `` I am running because of what Dr. King called 'the fierce urgency of now , ' `` he said . Covering ground from the Iraq war to the economy to health care , he said , `` there is such a thing as being too late -- and that hour is almost upon us . '' His campaign worked the crowd , passing out cards to sign up supporters and verifying that those who showed up are registered to vote . They handed out cards asking fans to provide their mailing addresses and phone numbers . The cards also featured an `` optional '' pledge to vote for Obama on January 26 . In his speech , Obama did not mention his chief rival by name . But he clearly referred to Sen. Hillary Clinton , saying that if he gets the Democratic nomination , his Republican competitor wo n't be able to say he ever `` supported the Iraq war . '' Watch how Winfrey 's campaigning could give Obama a boost » . Clinton was among the Democrats who supported a resolution authorizing force in Iraq in 2002 , though in a speech on the Senate floor she said she believed supporting the resolution could ultimately make war itself less likely . Obama was not in the Senate at the time , but gave a speech opposing the possibility of war with Iraq . Clinton has held a lead over Obama in South Carolina , where the Democratic primary consists largely of African-American voters . Clinton had a star of her own on the campaign trail for her Sunday in South Carolina -- her husband , former president Bill Clinton , who addressed a church in the morning . Check out some other celebrities who are endorsing candidates » . `` She has the best combination of mind and heart and strength of leadership and feeling for ... the problems of ordinary people of anybody I 've ever worked with , '' the former president said Sunday . Clinton was on the campaign trail with her mother and daughter . E-mail to a friend . CNN 's Peter Hamby and Suzanne Malveaux contributed to this report .
NEW : Largest crowd yet in the race to '08 , said Obama campaign . NEW : Officials estimate Obama people attended event in S. Carolina . `` Oprah-bama '' hit Iowa on Saturday ; S. Carolina , Iowa on Saturday .