New information released by the Congressional Budget Office reveals the government is not saving as much money as earlier predicted.
The big spending bill passed into law in April will cut the deficit by $122 billion over the next decade, less than half of what top lawmakers promised at the time.
Lawmakers had claimed their cuts would result in $315 billion in savings over the next decade, a prediction based on a Senate aide's study.
The CBO also said that increased military spending will raise the deficit by $3.2 billion this year.
The U.S. Treasury has the ability to avoid a default for now, but legislation to lift the so-called debt limit must include significantly greater cuts than last month's spending bill to avoid it in the future.