> Isn't restricting what people can lawfully do with their own land a form of expropriation?

Imagine you own land subject to a restrictive covenant. The restrictive covenant might actually have positive value to you – if the entire neighbourhood has a restrictive covenant prohibiting certain land uses, that gives your neighbourhood a character, people are willing to pay for the character the covenant enforces – maybe the existence of the covenant was actually a factor in convincing you to purchase this specific property. Suppose a legislative change invalidates the covenant – that's the government taking away from your land something you value about it. Isn't that an expropriation?

And I don't think there is a fundamental logical difference between a restrictive covenant on the title, and zoning as a government-imposed land use regulation. Some buyers choose a property because of its zoning, its zoning is something they know about and value; if the government changes the zoning, and that takes away from their property something they valued about it, isn't that an expropriation?

Note, I'm not arguing that removal of zoning and restrictive covenants is always wrong – maybe sometimes it is the right thing to do, all things considered. I'm simply arguing against the position "land use limitation = expropriation, removal of it = not expropriation" – even if something is expropriation, sometimes expropriation is justifiable