293 - USA, Inc.?

One concept that I often see people express is that the United States is now a private corporation. Those who make these claims often cite The District of Columbia Act of 1871 as proof. This "fact" is then used to support various positions or explain why or how certain acts of government take place. So let's look at The District of Columbia Act of 1871 and the Constitution of the United States to see for ourselves if we are no longer citizens of a union, but subjects of a corporation.