Twitter is going to have to learn the lesson that newspapers had to learn when they started accepting advertising: that when trust is your asset, you must run your service and your business according to principles of trust. Newspapers built church/state walls to demonstrate that they could not be bought by sponsors’ influence.
Twitter needs that wall. Every tech company fancying itself a platform does. Or it can’t be trusted and won’t be used and will lose value. Those are the economics of trust.