22. You know funny thing about the US drinking age. Drinking age is TECHNICALLY a state specific law, and not within the purview of the federal government. In fact, the 21st amendment specifically enumerates the ability of states to control alcohol related laws. However there is a federal law that ties together a drinking age of 21 and funding for federal highways in that specific state. This is an important precedent since it only incentivises a state to pass certain laws. This is considered by some to be indicative of the expansion of federal power and reduction in state power as a trend in US policy. Fun facts.