Word for someone who focuses on the smaller details of a bigger problem

I'm not sure if the title correctly describes what I'm looking for.

For example, there is a debate about the existence of something, and one party focuses on the small unexplained details in their opponents' argument and do not address the gaping holes in theirs.

Answer

For a single word, I suggest myopic:

Myopic is an adjective meaning shortsighted in every sense. Whether you need glasses or a new attitude, if you can't see the forest for the trees, you're myopic.
_{Vocabulary.com}

However, for the example you provided, I would describe the person as a lawyer.