A deadlock would send the thorny issue back to Congress as a whole.
Sen. Patty Murray, D-Wash., said Congress will still have to address the U.S. budget mess even if her group can't put a deal together.
If no deal is reached by Wednesday then automatic cuts kick in.
"I believe strongly that we still have the capability to come together to solve this problem," Murray told CNN's "State of the Union. "If the supercommittee can't do it, then I hope that Congress will."
Murray said the supercommittee's task boiled down to spending, revenue and entitlements. She said Democrats were not willing to give away guarantees that entitlement programs such as Medicare won't be eliminated entirely.
Sen. Rand Paul, R-Ky., countered that tax reform needed to be a major part of the supercommittee's negotiations rather than tax increases on the upper class. "The top 50 percent of wage earners pay 96 percent of the income tax," he said. "The rich and the middle class are paying their fair share."