In an interview with CNN, Merkley, a member of the Senate Budget Committee, said Republicans have unfairly focused on cutting Medicare and Social Security in negotiations, while neglecting to provide specifics on how they would raise new tax revenues.
Merkley's comments come as President Obama continues to negotiate with Speaker John Boehner (R-Ohio) and top Republicans over a deficit-reduction plan to avoid the combination of tax rate rises and spending cuts set to take effect in January.
Republicans responded this week to the president’s initial $1.6 trillion deficit offer with a $2.2 trillion proposal that includes $800 billion in new tax revenues.
Obama and Democrats have rejected the plan, insisting that any deal raise taxes on the wealthiest 2 percent of income earners. Republicans want to extend the expiring Bush-era tax rates across the board, while Democrats say they should be extended only for the middle class, forcing the wealthy to pay more.
GOP leaders instead want to raise revenues through closing loopholes and deductions and are refusing to concede on higher tax rates for the wealthy, in hopes of gaining leverage to force more spending cuts or to overhaul the tax code.
Both sides appear stalemated over tax rates, with Treasury Secretary Timothy Geithner on Wednesday warning that the administration was “absolutely” willing to go over the fiscal cliff if Republicans failed to concede on tax rates.
On Wednesday, Obama and Boehner briefly talked by phone over the negotiations. Aides refused to provide more details about the call.
Merkley said that secrecy in talks was fine, but negotiators needed to start focusing on details in order to craft a deal by year’s end.
"[If] there needs to be very specific negotiations that they need to keep them very private and contained for a while then so be it, but action is required," Merkley said.