Treaties are really important for how countries work together and follow the rules in international law. They are agreements that countries make to guide their behavior toward each other.

1. What is a Treaty and Why It Matters:

   • A treaty is a formal agreement between countries that is meant to be followed by law. As of 2023, there are more than 40,000 treaties registered with the United Nations. This shows how much countries depend on treaties to manage their relationships.

2. Basic Principles:

   • Treaties follow certain rules, like "pacta sunt servanda," which means treaties should be kept in good faith. This is very important because about 90% of countries are part of at least one major treaty. This shows that following treaties is a common practice among nations.

3. Different Kinds of Treaties:

   • There are two main types of treaties: bilateral (between two countries) and multilateral (involving many countries). For example, the Vienna Convention on the Law of Treaties, created in 1969, explains how treaties are made and enforced. It affects over 170 countries. Another example is the Paris Agreement on climate change, which includes 197 countries. This shows how countries can work together on big global issues.

4. How Treaties Affect Country Interactions:

   • Treaties help set rules and guidelines, reducing confusion and promoting cooperation between countries. For instance, countries that have signed arms control treaties have cut their nuclear weapons by more than 75% since the Cold War. This shows how treaties can help decrease conflicts and promote stability.

In summary, treaties are essential for laying down the rules that guide how countries interact. They help create predictability and foster teamwork in the international community.