One idea now making the rounds among some policy wonks is this: we can improve the social security system by changing the way adjustments to payments are made. SS recipients now typically get a cost of living allowance (COLA) to keep their payments at a constant level of spending power. Something like that is a very appealing idea in a system where inflation is more a feature of the system than a bug in it. But ... I'm sure I heard one of the contenders in the latest Republican Presidential debate saying. "We ought to link Social Security payments NOT to COLA, but to inflation. That would save some money and help preserve the system." In fact I think this was one of the relatively sane Republicans: Christie? Haley? The proposition is NOT self-defeating in any obvious way. COLA is not the only possible index of inflation, after all. One could measure inflation literally, by the expansion of the money supply. (Although the...