CHICAGO (AP) — A liberal group upset over potential cuts to Medicare, Medicaid and Social Security has delivered pledges to President Barack Obama's Chicago campaign headquarters threatening to pull their support.The Progressive Change Campaign Committee on Friday delivered what they say were 200,000 pledges from people who will refuse to donate or volunteer for Obama's re-election campaign if he cuts the entitlement programs.The campaign's chief operating officer met the group in the lobby of the downtown office building where the campaign's headquarters are located to collect the stack of pledges.Spokesman T. Neil Sroka says the Obama campaign values its volunteers. That's why he says they're disappointed they didn't get a better reception from the campaign.The grass-roots organization says it has 36,000 members in Illinois and more than 750,000 nationwide.