Is 「してはならないとさしとめる」 a double negative?

Question

In a Japanese dictionary entry for 禁止, I recently came across:

してはならないとさしとめること

1. してはならない: Literally this means "as little as (は) doing (して), doesn't become (ならない)". More idiomatically: "don't do this".

2. Xと差し止める. This means "prohibits X".

So putting these together, don't we get

It's prohibited that you don't do this.

which is the opposite of the intended meaning?

It's prohibited that you do this.

Question: Is the phrase "してはならないとさしとめる" a situation where you should interpret a double negative as if it weren't a double negative?

Answer 1

This と is for quoting. So it's equivalent to:

「してはならない」と差し止める

Or "prohibiting from doing, saying 'you can't do that'".