annul, a null

Annul or annul ( one word ) means to invalidate; to make legally void, as a law or contract--
They asked the judge to annul their marriage.
A court decision may annul the law, but it can't alter or rewrite it.

A null or a null ( two words, rhymes with annul ) describes something ( a ) without effect or consequence; something void or empty ( null )--
Without a signature, it's a null contract.
The set of people who have never used the internet may be a null set.

Now that you know that, you can say--
"This is a null statute for any practical purpose; it won't matter if the legislature decides to annul it."