“We are cutting ourselves to the bone,” Michael S. Nachmanoff, Federal Public Defender for the Eastern District of Virginia, told a subcommittee of the Judiciary Committee, which held a hearing on the effects of sequestration on the federal court system.

“We are on the verge of being crippled, and we’re a model of quality and efficiency, ” he said.

Federal defenders already were facing a 5 percent budget reduction when $85 billion in spending cuts began coursing through federal agencies in March, lopping another 5 percent from the budget this fiscal year. Some courts have limited the hours they hear criminal matters. Defenders across the country are taking up to 15 days without pay, forcing postponements in many criminal proceedings.

While the U.S. District Courts, federal marshals and U.S. attorneys were spared furloughs because the Justice Department was able to shift money into the accounts that pay their salaries, the defenders are paid from a different pot of money and got no such reprieve.

Nachmanoff said his busy court in Virginia recently turned down five big cases he described as “intensive, serious cases” because furloughs have left his stable of attorneys too shorthanded to take on the work.

The court system’s alternative is to hire private, court-appointed attorneys to represent indigent clients, since by law they must get a lawyer. They are paid from the same pool of money as public defenders. But they cost more, and according to some studies, are less experienced and less effective.

Nachnanoff told lawmakers that public defenders are expecting another hit to their budget of more than 20 percent in the fiscal year that starts Oct. 1, which would almost surely result in layoffs.

In a letter to the Judiciary Committee, a group of 40 former judges and prosecutors urged Congress to fully fund the defender program.

“These ill-conceived measures undermine not only the Federal Defender system, but the entire federal judiciary, without achieving any real cost savings,” they wrote of the sequestration cuts.

“They do extremely good work and it’s valuable work, ” Judge Julia S. Gibbons told the panel Tuesday. She described other sequestration-related cuts to pretrial and probation programs that she said could increase the risk of recidivism.

“We’ve had to seriously compromise some of our funds that go to keeping the folks we supervise from getting into trouble again,” said Gibbons, chair of the budget commitee of the Judicial Conference of the United States.

For some lawmakers on the panel, the plight of the defenders became a partisan proxy for the debate over the size and role of government.

“We don’t have the money to run the government, and we’re not just going to raise taxes every time, ” Sen. Jeff Sessions (R-Ala.) said.

But Sen. Richard Durbin (D-Ill.) said the cuts to the federal courts pointed up the need for a balanced approach to funding the government’s key services that would require raising taxes.