It would seem that Obama may be more than a small "s" socialist. At least, at one time, he was an active member of the Democratic Socialist Party's Chicago affiliate in the 1990s. Among other documentation, a 1996 issue of Progressive Populist magazine states,
New Party members and supported candidates won 16 of 23 races, including an at-large race for the Little Rock, Ark., City Council, a seat on the county board for Little Rock and the school board for Prince George's County, Md. Chicago is sending the first New Party member to Congress, as Danny Davis, who ran as a Democrat, won an overwhelming 85% victory. New Party member Barack Obama was uncontested for a State Senate seat from Chicago.
It's really not necessary to have these direct connections - Obama's stand on almost every issue make his (pragmatic and mixed) socialistic agenda quite clear.