The extent to which a separation of powers doctrine applies in the context of a parliamentary democracy such as Canada has long been a matter of debate. The author argues that this doctrine does have application in Canada and that it is violated by the blanket ability of some provincial executives to proclaim only portions of passed acts in force. This ability is rooted in the Interpretation Acts of a number of provinces and its effect, which the author equates with a line item veto, is to usurp the authority of the legislature and potentially upset the legislative compromise that ordinarily accompanies the passage of legislation. In the United States, the Supreme Court has found that bestowing a largely unfettered ability on the Office of the President to delete portions of legislation passed by Congress is not permitted by the US Constitution. Given the application of some form of a separation of powers doctrine in Canada, the author argues that the partial commencement of acts is also unconstitutional.