Stop politicians taking so much as a stick of chewing gum from anyone (or anything).
Publicly fund the electoral process.
Why is this important?
Up until close to election time, no restrictions on issue oriented (not politician oriented) messages as long as the messenger properly identifies themselves and additionally, if the messenger represents a group, the source of every penny in their pocket.
Our public airwaves shall be required for a period of time before an election for eligible candidates air their views and debate.
