International law interacts with domestic law through the principle of supremacy, whereby international treaties and agreements can take precedence over national legislation. When states ratify international treaties, these laws become part of their domestic legal framework, requiring compliance. However, the specific implementation of international law may vary based on a country's legal system and constitution. Additionally, some countries have mechanisms, like dualism or monism, that determine how international laws are integrated into domestic law. This interaction can affect issues such as human rights, trade, and environmental policies.