We went over this once before. This is a similar fallacy to the population one. There is no conceivable reason why Federal spending would have to be a certain percentage of GDP to get the job done. This rather feeble excuse is an attempt to disguise the fact that the rathole that the Feds pump money down at nearly sonic velocities is beginning to look less like a rathole and more like the yawning vortex of Charybdis.

Most of the things that government spends money on: defense, social spending, education, etc. do NOT get more expensive as GDP goes up, and should not require more money in proportion to GDP. In fact, as GDP increases logic would suggest that many spending programs, like social spending, should tend to decrease.

An analogy would be comparing me to Bill Gates. Bill Gates makes a little more money than I do, but the things he needs (food, clothing, shelter, medical care) don't cost him any more than they cost me.

Granted, he lives in a mansion instead of a townhouse, but that is by choice, not necessity. He would pay no more for the house I live in than I would.