Treaties and international agreements interact with a country's laws in interesting ways. Whether these agreements automatically become part of a country’s laws depends on how that country’s legal system is set up. Here’s an easier way to understand it:

1. Two Types of Systems:

   • Monist Countries: In monist countries, treaties automatically become part of the country's laws once they are accepted. For example, in the Netherlands, when a treaty is approved, it has the same power as laws made by the country itself.
   • Dualist Countries: In dualist countries, like the United Kingdom, treaties need extra steps to become part of the law. After accepting a treaty, the country must create new laws to follow it.

2. Some Examples:

   • United States: The U.S. is a dualist country. This means treaties are important, but they need new laws to be fully effective. For instance, when the U.S. agreed to the United Nations Convention on the Law of the Sea, Congress had to make new laws to apply its ideas.
   • Switzerland: Switzerland is a monist country. After accepting a treaty, it can be directly used unless the treaty says otherwise.

To sum it up, whether a treaty automatically becomes part of a country’s laws depends on how that country organizes its legal system.