Derogation is the partial repeal of a law, rather than total abrogation, where the entire law is revoked. There are a number of situations where derogation can arise and it can create legal tangles in some settings. When a law is derogated, legal authorities will need to decide the scope of the derogation and make decisions about how and if the law should be enforced.
A classic method for derogating a law is to enact another law that clearly conflicts with it. While lawmakers try to avoid doing this, sometimes it is inevitable. If such an event occurs, scholars may determine that part of the earlier law has been invalidated, but the rest of it still stands. Governments in the process of liberalizing sometimes end up derogating older laws because they cannot be struck down entirely, opening the way to changes in how those laws are enforced.
Temporary derogation can also occur, usually in emergency situations. Certain laws may be suspended if it is believed to be in the interests of public or national safety. In this situation, authorities decide which sections of a law will not be enforced and determine the duration of the derogation. Clear cause must be shown to demonstrate that the temporary suspension is necessary and documentation is typically generated for future reference.
Temporary delays in enforcement of a new law are also a form of derogation. If a government passes a law effective by a certain date and certain regions do not enact it by that date, it is considered derogated. This most commonly happens when regions lack the support to enact the law or feel it could destabilize them or run against their policy interests. They make arrangements ahead of time and receive an extension from the government. This allows time to put a system in place for enforcing the law.
Derogation can also be seen in negotiations over treaties and other agreements. Parties to a treaty may refuse to enforce certain components of the treaty while still agreeing to it as a whole. These signatories will have to abide by the sections of the treaty they have not derogated, and they may be pressured to change their policy position and consider endorsing the disputed section of the treaty. In other cases, accomplishing a partial agreement may be satisfactory to the parties involved in negotiating and drafting the treaty, and the derogation will be allowed to stand.