You mean the People don't control their government??
The US downsized after WWII. They kept the bureaucrats unfortunately, but let most of the military go. The prevailing logic against it was the horrible unemployment it would cause, much like the arguments today. I haven't studied the period enough to say what motivated them to do it anyway, but somehow it happened. It might be a good era to look at for ideas on how to force a downsize today.
The result was high economic growth and very low unemployment. The economic trends of the "Great Depression" caused by loose monetary policy and perpetuated (partly) by FDR's New Deal never really recovered until then.
Obviously that was a with tongue in cheek question.
This country is one hell of a lot different than it was in 1945. It's not going to downsize. You can bet your life on that.