Imagine if we could analyze a current law (ex. Computer Fraud & Abuse Act) and tweak the parts that are being abused or used in a way that they weren't intended. Or each time a law is added (merged with Master branch) we could see who voted in favor of that law (i.e. greater transparency). Other countries could take our constitution/laws up to a certain point (commit) and then branch off and implement their own approach. There are many ways we could utilize git to improve how laws are created/modified/deleted.
Laws are just rules and processes humans have come up with in a best effort to guide society in the right direction, no different than code is just logic programmers come up with to direct servers and clients to interact in a desired way. We've realized the importance of version control in the software realm, it's time to take it's powerful properties and apply it to the political sphere.