もんじゃない translation attempt

Question

I'm reading a book, and the antagonist was released from prison early because he bribed the district prosecutioner.

The main character says: 野郎。。。　法なんてあってねーようなもんじゃねーか

This is my translation: Bastard... It's like there is no law (lacking in lawfulness?)

But I'm not sure how もんじゃない functions here. I know もんだ/です can function as giving a reason for something. Is もんじゃない used similarly but ない is used because it is a negative verb?

Answer 1

Your translation attempt is spot-on.

This もん is a simple noun, "thing". あってないようなもの is a set phrase that means "a thing that exists but is like nonexistent," or "a thing that's virtually nonexistent". It's commonly used to describe how something is useless or meaningless.