Winfrey has exerted political influence, endorsing presidential candidate Barack Obama in the 2008 presidential election. This is the first time she has publicly made such an endorsement. Winfrey held a fundraiser for Obama on September 8, 2007 at her Santa Barbara, CA estate. In December 2007, Winfrey joined Obama for a series of rallies in the early primary states of Iowa, New Hampshire, and South Carolina. The Columbia, South Carolina event on December 9, 2007 drew a crowd of nearly 30,000, the largest for any political event of 2007. An analysis by two economists at the University of Maryland, College Park estimated that Winfrey's endorsement was responsible for between 423,123 and 1,596,995 votes for Obama in the Democratic primary alone, based on a sample of states which did not include Texas, Michigan, North Dakota, Kansas, or Alaska. The results suggest that in the sampled states, Oprah’s endorsement was responsible for the difference in the popular vote between Barack Obama and Hillary Clinton.