Sen. Kent Conrad (D-N.D.) held fast to the idea of health insurance cooperatives Sunday while Sen. Arlen Specter (D-Pa.) claimed that the public option was going to garner more support than previously expected.

The two Democrats, symbolic of the intra-party disputes that are being hashed out over the specifics of healthcare reform, appeared on "Fox News Sunday" along with Sen. John Thune (R-S.D.), who predicted that a government-run public option would be "a very heavy lift" to get through the Senate.

"I will not support any public option tied to Medicare levels of reimbursement," said Conrad, chairman of the Senate Budget Committee, when pressed by host Chris Wallace on whether he could back a bill that contained a public option. While repeatedly pressing the idea of health insurance co-ops, Conrad indicated potential compromise in the realm of the public option "trigger" advanced by Sen. Olympia Snowe (R-Maine).

"There's at some point a principled compromise," Conrad said.

Specter held fast to the public option when pressed on whether he could accept a bill that didn't include it.

"I'm not prepared to recede at all," Specter said. "I think the public option is gaining momentum. ... I'm not going to step back a bit."

Specter, a former Republican until recently, cited the support of "respectable Republicans" such as former Senate majority leaders Bob Dole (Kan.) and Bill Frist (Tenn.).

Thune stressed, however, that "Republicans reject the idea of government-run healthcare" and predicted that even co-ops would be a "gateway to a government plan."

On "Meet the Press," Sen. Chris Dodd (D-Conn.) said that the public option stood a good chance of passing and dismissed the notion that Republicans were being excluded from the process, noting that more than half of GOP amendments were accepted during markup.

Sen. Jon Kyl (R-Ariz.), however, characterized the healthcare reform process as "being written in Harry Reid's office behind closed doors," and speculated that Democrats may offer the public option in a different form to make the package more attractive.

"What are the alternatives here if we do nothing?" Dodd said. "The impact of doing nothing is so much more costly."

On ABC's "This Week," White House senior adviser David Axelrod sounded an optimistic note, saying the administration would get bills passed in both houses, take them to conference and hammer out agreements over the details.

"I think this thing is going to be adjusted as it goes along," Axelrod said.

White House senior adviser Valerie Jarrett echoed the optimism on "Meet the Press."

"We are right on the brink of delivering for the American people," Jarrett said.