“On the actual campaign trail, you are hearing virtually none of the kind of blatant honesty that we need about what changes would fix this situation,” said Maya MacGuineas, the president of the Committee for a Responsible Federal Budget, an advocacy group in Washington that promotes fiscal restraint.

The parties share blame for the current fiscal situation, but federal budget statistics show that Republican policies over the last decade, and the cost of the two wars, added far more to the deficit than initiatives approved by the Democratic Congress since 2006, giving voters reason to be skeptical of campaign promises.

Calculations by the nonpartisan Congressional Budget Office and other independent fiscal experts show that the $1.1 trillion cost over the next 10 years of the Medicare prescription drug program, which the Republican-controlled Congress adopted in 2003, by itself would add more to the deficit than the combined costs of the bailout, the stimulus and the health care law.

The House Republican leader, John A. Boehner of Ohio, has called for immediate cuts in “non-security discretionary” spending to prerecession 2008 levels. Independent analysts say that would require eliminating about $105 billion  or more than 20 percent of spending by departments like Education, Transportation, Interior, Commerce and Energy  a level of reductions that history suggests would be extremely hard to execute. (Since 1982, nonmilitary discretionary spending has never dropped by more than 5.5 percentage points in any given year.)

At the same time, most Republicans are calling for the permanent extension of all Bush-era tax cuts, which would add $700 billion more to the deficit over the next 10 years than President Obama and Democratic leaders have proposed by continuing only some of the lower rates.