Appointments, special elections, substitutes...

Lots of discussions these days regarding the right mechanism to substitute the current system to replace Senators (or Representatives) when they get another position (e.g. President of the US...) (or die etc.) - all the discussion in the US centers on special appointments (by Governors - see: ridiculous scandal in Illinois and ridiculous comedy in NY...) vs special elections. Latest take by Matt Yglesias here.

A simple system is the one in place in France, for instance: every representative (député) is elected at the same time as his/her replacement (suppléant) - funny that this does not exist in the US, and that no one even appears to be thinking about it...Funny on the other hand that the US has a system of substitutes for the executive branch (Vice-President, Lieutenant-Governors) - and France has none, but has substitutes for the legislative branch...