I saw a reference to (US Representative) Paul Ryan’s plan to kill Social Security and Medicare, but only for people currently under 55 (he doesn’t say “kill” of course, but if it was going to make things better he wouldn’t need to exempt everyone likely to care directly about the issue) and it reminded me to post this.
A policy like this has what economists like to call a time-inconsistency problem. To get the policy approved, Ryan needs the votes of people currently over 55 (hence the exemption) and in the current US situation, any Republican majority has to rely heavily on older voters. Say the plan passes. Sooner or later, the combination of demographics and the electoral pendulum means that the Repubs will be out, and the new primarily majority will face three choices (a) Repeal the whole thing if they can do so before it comes into force (b) Keep on paying high taxes to fund benefits they will never receive for the benefit of the selfish old so-and-so’s who voted to cut the rope once they had reached the top; or© extend the same cuts to the (as of 2011) over 55’s, and claw back some money for themselves.
If I were an over-55 Republican, I don’t think I would want to count on (b)
* The original grandfather clause was a Jim Crow rule limiting the franchise to people whose grandparents had held it before the Civil War. The UK adopted something similar in relation to immigration in the 1970s. These examples give some good reasons why grandfather clauses (exempting existing participants in a system from unfavorable rule changes) are bad policy in general, though there may sometimes be exceptions