empathy should be a basic requirement for any political office in a democracy

Empathy should be a basic requirement for participation in society, period.

The whole concept of a social contract is based (and dependant) on empathy.

You lack empathy, you get put into a mental hospital to get it fixed, and to prevent you from harming others and society in general.

If your case is currently incurable (probably because it's not acquired but due to some as yet unfixable brain malformation), you get taken care of as well as possible for the rest of your life (or until a cure is developed), but prevented from ever interacting with society.

This alone would fix most of humanity's problems.