I would not be surprised that Obama might have had or has today associations with members of the Communist Party USA. He has travelled among fire-breathing 1960s radicals since the 1980s; and his political-economics is sufficiently dead-brained to have been still-born from the loins of the expiring Communist Party. Hillary said, some time back, that Obama hasn't been sufficiently vetted; how wise she was.
Update. May 29, 2008. In his 1996 Illinois Senatorial campaign, Obama sought out and received the support of a Marxist political organization, some of whose members were also members of the Communist Party, USA, worked for Obama's campaign.
Update. May 29, 2008. Obama's close connection to ACORN--which would make sense, given his early career in community organizing.
Update. July 3, 2008. One of Obama's youthful mentors was Frank Marshall Davis, a black communist.
Update. July 8, 2008. What Barack Obama Learned from the Communist Party. An extensive discussion in The American Thinker by Andrew Walden.