The liberal Progressive Change Campaign Committee is launching a petition drive to rally President Barack Obama’s own campaign supporters to pressure him to stand up for a public insurance option as part of a sweeping health care overhaul. The push comes as White House aides are signaling that Obama will not throw his support behind such a provision when he makes a critical public pitch for reform Wednesday in an address to a joint session of Congress. “We worked so hard for real change,— the petition reads. “President Obama, please demand a strong public health insurance option in your speech to Congress. Letting the insurance companies win would not be change we can believe in.—The group claims an e-mail list of 150,000 people, but its organizers are trying to take their campaign viral, asking supporters to find more signatures from others who volunteered, donated or voted for Obama last November. On top of the petition, the group is planning an advertising campaign that will feature the voices of signatories.