The U.S. government is an insurance company with an army:
The vast bulk of its spending goes to the big five: Social Security, Medicare, Medicaid, defense, and interest on the debt.
But what about recent deficits? They’re caused mainly by a fall in revenue and a mostly automatic increase in spending on safety-net programs. Oh, and the federal government has been providing aid to state and local governments, largely to limit layoffs of schoolteachers.
And if you want smaller government, either you’re talking about cuts in the big five, or you have no idea what you’re talking about.
I disagree with Krugman here, a bit, because I see a third possibility. You could be advocating smaller government without cuts to the big five because you're trying to mislead people.