Tax cuts enacted in 2001 and 2003 under President George W. Bush are scheduled to expire at the end of this year. If Congress allows that to happen and if other laws remain unchanged, the report said, the deficit will fall to $585 billion in 2013 and $345 billion in 2014.

In other words, the report suggests, doing nothing may be the most straightforward way for Congress to slash the deficit, a goal espoused by lawmakers in both parties. Under an alternative scenario, the deficit would still drop below $1 trillion and decline as a share of the economy for several years if Congress extended the Bush tax cuts and reversed other budget-balancing policies.

This year’s expected deficit of $1.1 trillion would amount to 7 percent of the economy, which is nearly two percentage points below the share recorded last year “but still higher than any deficit between 1947 and 2008,” the report said. “Over the next few years, projected deficits drop markedly, averaging 1.5 percent of G.D.P. over the 2013-2022 period.”

Still, the budget office said, the government will need to continue borrowing to fill the gap between spending and revenues, and the total federal debt — the accumulated total of such borrowing — will rise to $21.6 trillion in 2022, from the current level of $15.2 trillion. And net interest payments on the debt would nearly triple, to $624 billion, the report said.

The budget office said it would cost $5.4 trillion if Congress continued the tax cuts enacted in 2001 and 2003 for another 10 years.

Mr. Obama and many Democrats want to continue most of those cuts for individuals with incomes under $200,000 a year and couples with incomes under $250,000 a year.

Because of the recession, total federal revenues declined in the 2008 and 2009 fiscal years and are just now returning to the level recorded in 2008. However, Mr. Elmendorf said, corporate tax payments are lower than expected and have not kept pace with the growth of corporate profits, so the average corporate tax rate has continued to decline.