This chapter explores the question of a 'public purpose' requirement for the taking of property, and the nature of any 'right to keep' as an incident of ownership, through the prism of Irish constitutional property law. It illustrates how the progressively framed Irish constitutional property clauses have translated into a weak public purpose requirement that retains flexibility for the elected branches of government to determine that deprivation of property is warranted in a wide range of circumstances. It draws lessons from Irish constitutional property law for progressive property attempts to address the 'public purpose' question in ways that both preserve the State's ability to acquire or abrogate property rights in the public interest and protect owners' and their communities against unfair exploitation.