I understand that sanctions in general work in a variety of ways, such as preventing new technologies from being developed, encouraging unrest among the populace, etc.
However, it appears to me that right now North Korea is at a very advanced point in its nuclear program. It also appears to be highly motivated to develop a functional, deliverable nuclear weapon.
Taking this into consideration, and assuming that the end goal of any future sanctions is to prevent North Korea from continuing its research into nuclear weaponry, how exactly are further sanctions intended to accomplish this?
As an example, we can take the proposed oil embargo of North Korea. What is the assumed causal link between implementing such a measure and North Korea abandoning its efforts to develop a functional nuclear weapon?