With every act of congress passed, there is a section that defines what certain terms in said act mean. In U.S.C. Title 28, for example, the term "United States" is define is section 3002(15) as "a federal corporation". Well, 26 U.S.C., the income tax code, also has a defintions section at Section 7701.

For Immediate Release 05/26/2017

The judgment of a court of record whose jurisdiction is final is as conclusive on all the world as the judgment of this court would be. It is as conclusive on this court as it is on other courts. It puts an end to inquiry concerning the fact by deciding it.

Ex parte Watkins, 3 Pet., at 202-203. [cited by SCHNECKLOTH v. BUSTAMONTE, 412 U.S. 218, 255 (1973)]

Not too long ago I read a case about a man who challenged the city within which he lived, claiming that the town and therefore the government did not have jurisdiction, because it was a corporation. One of the cases cited in his defense was Bank of United States v. Planters' Bank of Georgia, 22 U.S. 9 Wheat. 904 904 (1824) in which was opined,