The 3rd amendment is a very useful piece of history. It demonstrates how reactionary our declaration and constitution actually are. Our bicameral system is the result of paranoia from smaller states. Actually, a lot of our system is based on states' inability to get along... But the 3rd amendment was a reaction to a specific action by the British government prior to the war. Soldier quartering was uncommon even then. That we enshrined protection against it as an important right is rather silly. It almost never comes up.