Several dozen former Obama campaign supporters gathered in front of the White House shortly after noon to demand that the president insist on the creation of a public option for health insurance – and threatened to work against Obama in 2012 if he doesn’t.

The Progressive Change Campaign Committee will hold an event outside the White House today where former staffers of President Obama’s 2008 campaign will call on the president to sign health care reform with a public option.

Two major liberal groups launched petition drives Thursday demanding that President Obama endorse a public-insurance option as part of his drive for health-care reform.