Antonym for "come into effect"?
If the law has been taken off the statute books, it has been repealed.
repeal vb (tr) {Collins}
(Government, Politics & Diplomacy) to annul or rescind officially (something previously ordered); revoke
these laws were repealed
If it is still on the relevant statute books but is no longer enforced, probably because it is seen as no longer necessary or helpful (or it is now realised that it always was petty, unjust or unenforceable), it is said to have fallen into abeyance.
in abeyance {Longman Dictionary of Contemporary English}
something such as a custom, rule, or system that is in abeyance is not being used at the present time
fall into abeyance (=no longer be used)
The Forest law fell into abeyance.
To abolish, according to MW:
to end the observance or effect of (something, such as a law)
Real-world example in the NYT:
"The South African Government said today that it had decided to abolish the laws forbidding marriage and sex across racial lines."
It can also be used for something that is the subject of a law, for example if there were a law allowing slavery, successfully voting to repeal that law may be put like this:
We voted to abolish slavery.