Dr Eric Crampton: Open markets are still the best way to a fair economy

The strongest protection tenants can have is plenty of other potential places to rent, from different landlords eager to rent them a home.

When zoning rules make it very difficult to build new housing, existing landlords do not face much potential competition. If every landlord has dozens of tenants racing to submit applications as soon as a property becomes vacant, landlords will have a lot of power over their tenants. And rents will be high.