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 Company. v. C.I.R., 227 F.2d 16, 19-20 (3rd Cir. 1960).) Any other taxes are typically called "indirect taxes," because they tax an event, rather than particular or property by itself. (Steward Machine Co. v. Davis, 301 U.S. 548, 581-582 (1937).) What was a straightforward limitation on the power of the legislature based on th...