What International Law Principle Prevents Using Domestic Law to Excuse Treaty Violations?

The correct answer is D、 Non-derogation principle.

Here's why:

• Non-derogation principle: This principle, fundamental to international law, asserts that a state cannot use its internal or domestic laws as a justification for failing to uphold its commitments under international agreements or treaties. In essence, a country can't simply pass a law that contradicts its international obligations and claim it's off the hook.

Let's look at the other options:

• A、 Pacta sunt servanda: This crucial principle underpins the entire system of treaties and international agreements. It translates to 'agreements must be kept.' While essential for international law, it doesn't specifically address the issue of using domestic law as a justification for non-compliance.* B、 Reservations principle: This principle deals with the ability of states to modify or exclude certain provisions of a treaty when they agree to be bound by it. It focuses on the formation of treaty obligations, not on excusing breaches.* C、 Non liquet principle: This principle comes into play when a court or tribunal finds itself unable to reach a decision due to a gap or ambiguity in the law. It relates to situations where the law provides no clear answer, not to justifications for non-compliance.

In summary: The Non-derogation principle is the key principle that prevents states from sidestepping their international legal responsibilities by pointing to their domestic laws as an excuse.