Sen. Mark R. Warner, D-Va., has assembled a group of 36 senators from both sides of the aisle to pressure the deficit-reduction "supercommittee" to go beyond the $1.5 trillion in reductions sought by the president and Congress in last month's debt deal.

The group of 18 Republicans, 17 Democrats and one independent — more than a third of the Senate — on Thursday urged the committee to identify $4 trillion in total reductions over the next decade.

As part of the eleventh-hour debt deal, $1 trillion in reductions were immediately enacted. The supercommittee then was tasked with identifying an additional $1.5 trillion. To meet the request of Warner's group, the committee would need to double that goal.

"We're trying to say, if you go bold … we'll be there to support you," Warner said in a phone interview Thursday.

The 36-member group, which Warner partnered with Sen. Saxby Chambliss, R-Ga., to assemble, asks that entitlement reform and tax reform be included in the effort.

It also urges the committee to use the work of previous bipartisan plans — such as the $3.7 trillion "Gang of Six" debt-reduction effort that Warner and Chambliss led — as a framework.

That sweeping plan, unveiled as the debt deal standoff came to a head in late July, failed to gain traction as congressional leaders scrambled to strike a short-term deal to raise the debt ceiling with time running out before the nation defaulted on its debt.

The resulting deal, Warner said, is "not nearly bold enough to truly fix our nation's balance sheet."

Asked if Republican resistance to tax increases would make achieving the $4 trillion total impossible, Warner noted that the Gang of Six effort would have lowered overall tax rates while increasing revenue through the elimination of loopholes and subsidies.

Warner pointed out that the only time the U.S. has balanced its budget or approached a surplus in the past 70 years has been when revenues and expenditures were both between 19 to 21 percent of gross domestic product.

"Now we've got spending at 25 percent, revenues at 15 percent," he said. "It doesn't take a rocket scientist to figure out that if you're going to get close to balanced, it needs to be somewhere in the middle."

The committee's report is due to Congress on Nov. 23, with a vote required a month later.