The courts have generally held that direct taxes are restricted to taxes on people (variously called capitation, poll tax or head tax) and property. (Penn Mutual Indemnity Organization. v. C.I.R., 227 F.2d 16, 19-20 (3rd Cir. 1960).) Any other taxes are commonly referred to as "indirect taxes," basically because they tax an event, rather than a person or property by itself. (Steward Machine Co. v. Davis, 301 U.S. 548, 581-582 (1937).) What seemed to be a straightforward limitation on the power o...