Add requirements that someone needs to have x years of experience in given offices.
I think it highly depends what role politicians are expected to fill.This should probably be in politics... To answer you though, if you put in a vetting process, you have taken the first step towards dictatorship. If X is qualified but not Y, why bother having elections to begin with? Naturally this only applies to republics, or nations with an electoral process. Kings and kingship needn't worry about the bleating of the peasants, and there were some truly awful, terrible kings, despite having 'experience'.