International law: it's a big network of agreements that countries follow, most of the time, to help the whole international system run as smoothly as possible, but of course, there's a problem.
Let's say one country has a law about human rights and international law has a different one.
If someone in that country commits a human rights crime, are they subject to their own country's laws or to international law?
Well, according to the principle of sovereignty, each country has legal authority within its own territory.
International law can't intervene, but some say it provides an ethical example, which states should follow.
Some countries don't face this situation.
'Monist' countries, like the Netherlands, believe that international and national law are a single system, which is handy because many of the international courts are found in the Netherlands.
But other countries, like our imaginary country, believe they are separate systems.
We call this approach 'dualist'.
