Law
Federalism and International Treaty Implementation
Quick fact
In federal systems like the US, the federal government can ratify a treaty, but if it requires changes in areas reserved to states (like education or local environmental rules), the national government may be powerless to force compliance, leading to international embarrassment and domestic legal battles.
Why this is interesting
You might think a country's government can simply sign an international treaty and that's it. But what if the treaty covers issues that, inside the country, are decided by local states or provinces, not the central government?