- Make all ads publicly viewable along with the targeting demographics. So everybody can see, for example, that a politician is pushing xenophobia to older people.
- Some kind of ad "fake news" score associated with a campaign. This one is difficult, but I could imagine a score based on a mixture of "fake news scoring providers" from across the ideological divide and news orgs.
The point is to give voters some transparency into what a politician is actually campaigning on.