Constant dollars means dollars adjusted for inflation. I'm sorry if I'm losing you here.

Your family analogies are flawed. The government is not the source for everything we need. You still haven't specified what Federal expenses must go up with general population or GDP. I'm talking about what government needs to do, not what it wants to do, which is pretty much everything.

Federal entitlements for the elderly come to mind, which are indeed affected by the number of elderly, but that's about it. Really, do you think that if population doubled, defense spending should double for some reason? Why?

In hard times, normal people cut expenses. Only the government thinks it can't possibly do without more money every year.

Anyway, spending has gone up far faster than population growth. The Federal budget is four times what it was in 1966 in constant dollars. Population went up by a factor of 1.5

The Federal government is a bloated monstrosity. Admitting it is the first step to fixing it.