1. reduce or simplify something to its most basic or important aspect
the issue boils down to
The expression 'boils down to' takes the literal meaning of reducing and concentrating a liquid through boiling, and transfers it to the figurative reduction of something to its most essential aspect. For example, if a situation or problem boils down to something then that is the main reason for it. It is commonly used in both a social and professional context and is similar to the phrase 'in a nutshell.'