The ruling is hilarious. An Indiana mayor awarded a $1.1 million dollar contract to a truck dealership, then went to the dealership afterwards and said "I need money." He asked for $15k in cash, and was given $13k.
According to the SCOTUS this is not bribery because a bribe is an award for pre-agreed actions that is quid pro quo, and maybe the dealer just happened to feel generous to the person responsible for awarding them a lucrative contract after the fact. Only money in burlap sacks with dollar bills on them, with a person handing it over with a contract saying "this is a bribe" count as a bribe. Anything else is just a sparkling gratuity.