Disallowance and reservation in Canada

Disallowance and reservation are historical constitutional powers in Canada that act as a mechanism to delay or overrule legislation passed by Parliament or a provincial legislature. In contemporary Canadian history, disallowance is an authority granted to the governor general in council (federal cabinet) to invalidate an act (also called a "statute") passed by a provincial legislature. Reservation is an authority granted to the lieutenant governor to withhold royal assent from a bill which has been passed by a provincial legislature; the bill is then "reserved" for consideration by the federal cabinet.

In Canadian constitutional law, the powers of reservation and disallowance of federal legislation formally remain in place in Sections 55 and 56 of the Constitution Act, 1867, and are extended to provincial legislation by Section 90. The initial intent of disallowance, and its practice for the first few years of Confederation, was considered a means of ensuring parliament enacts legislation compliant with the constitution.

Since Confederation in 1867, the Government of the United Kingdom has only disallowed one federal law, while the government of Canada has disallowed 112 provincial laws, with the most recent instance occurring in 1943 when Alberta's law that limited land sales to Hutterites and other "enemy aliens" was invalidated. The power of reservation has been exercised 21 times by the governor general, all before 1878, and 70 times by various lieutenant governors, with the most recent case in Saskatchewan in 1961 when the lieutenant governor reserved assent on a bill related to mining contracts.