B.A(S). => LLM
This is incorrect in the US, where the LLM is a (post-)graduate degree that follows the initial degree in law. In the US, the initial degree is now the JD (Juris Doctor), though in earlier times (and still today in other countries) it could be called LLB (bachelor of laws).
To answer tdolittle's question, in the US a masters degree is generally considered to be more advanced or complete than a diploma - though I'm sure there are exceptions.