What legal principle requires the government to compensate property owners when seizing their property for public use?

The principle that mandates the government to compensate property owners when taking their property for public use is known as "just compensation." This legal doctrine stems from the Fifth Amendment to the United States Constitution, which states that private property shall not be taken for public use without just compensation. This requirement ensures that property owners are fairly compensated for their losses when the government exercises its power of eminent domain, which allows it to acquire private property for public projects such as highways, schools, or parks.

Fair market value relates closely to just compensation but specifically defines the amount a willing buyer would pay a willing seller in an open market. Market value assessment is a term more commonly associated with appraisals done for taxation purposes, rather than the compensation related to property seizure. Value at time of sale might imply an assessment at a specific point, but does not encompass the broader legal obligation of the government to compensate property owners fairly. Thus, just compensation is the correct principle ensuring that property owners receive remuneration commensurate with the value of their property taken for public use.