"I urge you to bring to the floor as soon as possible a tax bill to ensure that the tax reductions currently enjoyed by middle class Americans continue and the breaks for the super-rich expire to help pay down the national debt," he wrote on Aug. 19.
Murphy's call comes as a growing chorus is urging the continuation of all the Bush tax cuts to keep the economy from backsliding into another recession.
Congressional Budget Office Director Doug Elmendorf on Thursday told reporters that a short-term extension of these breaks would lower unemployment and boost GDP in 2011.
The Joint Committee on Taxation recently reported that extending all of the tax cuts would, on average, give millionaires a $100,000 tax refund in 2011.
Murphy argues that strategy would saddle future generations with an additional $1 trillion in debt.
"[Do] we really need to provide each of these wealthiest individuals with nearly $100,000 in additional tax cuts next year?" he wrote. "That's nearly $1 trillion in more debt that the children of hardworking middle class families will be asked to cover, just so the super rich can become even wealthier."
Debate over whether to extend the Bush tax cuts is expected to heat up when lawmakers return to Washington after their August recess.