The document outlines the process for amending the US Constitution through formal amendments. It describes how amendments can be proposed by a two-thirds vote in Congress or national convention, and then ratified by three-fourths of state legislatures or conventions. This process reflects the principles of federalism by involving both federal and state actors, and popular sovereignty by basing it on votes of elected representatives. In total, 27 amendments have been successfully added to the Constitution through this formal process.