On Aug. 7, 1978, economist Milton Friedman added his powerful voice to the discussion. Writing in Newsweek magazine, he said, "the only effective way to restrain government spending is by limiting government's explicit tax revenue--just as a limited income is the only effective restraint on any individual's or family's spending."
It's pretty obvious where Friedman's metaphor breaks down: a family has no source of spending other than its income. It can get a loan for a house, for example, but if a family isn't credibly repaying its loans it will not be able to get any further loans. Government can fail to repay a whole bunch of loans and continue to get more. This needs to get more attention... it's going to be very relevant for domestic American politics for the next few decades as we try to get our fiscal house in order.