This document provides details on the constitutions of the USA, India, and Switzerland. It outlines key features of each constitution such as their amendment processes and the frameworks they establish. The USA constitution introduced new concepts like federalism, separation of powers, and judicial review. It can be amended through a two-thirds congressional majority and three-fourths of state legislatures. India has the world's longest constitution blending rigidity and flexibility, and amendments require simple or special majorities. Switzerland's federal constitution establishes a democratic republic with direct democracy, federalism, and a mixture of parliamentary and presidential systems.