 Locke’s understanding of separation of powers is complicated by the doctrine of prerogative. Prerogative is the right of the executive to act without explicit authorization for a law, or even contrary to the law, in order to better fulfill the laws that seek the preservation of human life. A king might, for example, order that a house be torn down in order to stop a fire from spreading throughout a city (Two Treatises 2.159). Locke defines it more broadly as “the power of doing public good without a rule” (2.166). This poses a challenge to Locke’s doctrine of legislative supremacy. Locke handles this by explaining that the rationale for this power is that general rules cannot cover all possible cases and that inflexible adherence to the rules would be detrimental to the public good and that the legislature is not always in session to render a judgment (2.160). The relationship between the executive and the legislature depends on the specific constitution. If the chief executive has no part in the supreme legislative power, then the legislature could overrule the executive’s decisions based on prerogative when it reconvenes. If, however, the chief executive has a veto, the result would be a stalemate between them. Locke describes a similar stalemate in the case where the chief executive has the power to call parliament and can thus prevent it from meeting by refusing to call it into session. In such a case, Locke says, there is no judge on earth between them as to whether the executive has misused prerogative and both sides have the right to “appeal to heaven” in the same way that the people can appeal to heaven against a tyrannical government (2.168).