The best way to measure government is not by volume, but by what you might call the Achievement Test. Does a given policy arouse energy, foster skills, spur social mobility and help people transform their lives? Over the years, America has benefited from policies that passed this test, like the Homestead Act and the G.I. Bill. Occasionally, the U.S. government has initiated programs that failed it. The welfare policies of the 1960s gave people money without asking for work and personal responsibility in return, and these had to be replaced. The welfare reforms of the 1990s involved big and intrusive government, but they did the job because they were in line with American values, linking effort to reward…

The exciting thing about this moment is that everything is on the table. Thousands of policy proposals are floating around, thanks to the various deficit commissions and policy entrepreneurs. As the parties argue about the debt limit and the rest, it should be possible to take items from both and ram them into a package that cuts consumption spending in order to make investment spending more affordable.

How big will the resulting government be? That is a secondary issue. If a policy enhances achievement, we should be for that thing. If it displaces investment, we should be skeptical of it. Quality, not quantity, matters most.