When a public body acts in a way that deprives someone of a protected property or liberty interest, the constitution requires process — and challenges succeed on process far more often than on substance.
Is there a protected interest? Property interests are created by an independent source such as a statute, ordinance or contract, not by the constitution itself. A licence already held, a permit granted, tenured public employment and certain benefits are typical examples. A mere expectation or a purely discretionary benefit generally is not.
What process is due? Assessed by weighing the private interest affected, the risk of erroneous deprivation under the existing procedures and the value of additional safeguards, and the government’s interest including administrative burden. In practice the core is notice and an opportunity to be heard by a neutral decision-maker, before the deprivation where feasible.
Common failures by public bodies: notice that does not state the grounds with enough specificity to permit a response; a decision-maker who investigated, prosecuted and decided; a hearing at which the evidence relied on was never disclosed; and a written decision that does not state reasons, which makes review impossible and is itself often fatal.
For a person affected: object to the process on the record at the time. Procedural objections not raised before the body are frequently unavailable on review.