Chapter 5 of Public Choice Theory and the Illusion of Grand Strategy taught me the most.  Hanania provides a great survey of what we know about the effects of trade sanctions – and then gets meta.

He starts by emphasizing the terrible harm of sanctions.  “Humanitarian” exceptions mean little in practice:

Sanctions regimes that target the economy of a country usually have humanitarian exceptions. Despite this, other regulations usually serve to limit their effectiveness. For example, federal law ...