Reading Jonathan Healey's The Blazing World and Curtis Yarvin's recent article on the difficulty of reforming the US Government through the exercise of the executive power has got me thinking about the nature of the parliamentary power. The parliamentary power is commonly said to be "the purse strings," e.g. the power to, if a tax-funded organization such as a police department flagrantly violates the law or otherwise acts in ways intolerable to the parliament or those who it represents, cancel their budget, but while this has some descriptive merit, it fails to explain why, how, and under what circumstances such a power emerges. "Because the written constitution says so" is a triply bad explanation, first because it fails to explain why written constitutions tend to identify and separate some particular powers with some consistency across contexts, second because it fails to account for the existence of states with well-articulated constitutions that, while they may be described in writing, were not established through a formal written constitution, and third because it does not explain why, how, and under what circumstances people can be persuaded or compelled to obey a written constitution.

I prefer functional explanations; if there is a sufficiently strong use case for some expensive form of organization, then existing institutions that fill that role have some bargaining power when they can credibly threaten to withdraw their services. This is sufficient to establish distinct powers.