Politicians only get to the top because they have no qualifications to detain them at the bottom.
Variants
People who reach the top of the tree are only those who haven't got the qualifications to detain them at the bottom.
To be gentle, tolerant, wise and reasonable requires a goodly portion of toughness.
Children are the only form of immortality that we can be sure of.
All the hideously calculated hypocrisy of men when they commit a murder in the name of justice.
Quote text and notes from Wikiquote: Peter Ustinov (page history), available under CC BY-SA 4.0. Source quality and labels are our own summary of what Wikiquote records.