The Legal Imperative: Must versus Shall

(Posted March 11, 2021)

In normal conversation, if I tell you that you must do something, that would be understood as an imperative command.  However, lawyers have undergone years of intensive training to make us “think like lawyers” rather than like normal people.  Along this line, traditionally, in legal drafting, the convention has been to use the word “shall” to indicate an imperative.  For example, section 2(1) of the Income Tax Act reads “An income tax shall be paid, as required by this Act, on the taxable income for each taxation year of every person resident in Canada at any time in the year.”

This drafting convention has been enshrined in the federal Interpretation Act, which is one of the first stops a lawyer would make in dealing with a question of statutory interpretation.  Section 11 of that Act reads “The expression ‘shall’ is to be construed as imperative…”

Something changed in the past few years, however.  Federal legislation has been drafted using the term “must” to express an imperative.  For example, section 10(1) of An Act respecting First Nations, Inuit and Métis children, youth and familiesreads “The best interests of the child must be a primary consideration in the making of decisions or the taking of actions in the context of the provision of child and family services in relation to an Indigenous child…”  Representatives of the Department of Justice have explained to me that using “must” to express an imperative is now the standard for legislative drafting, and that this is part of a move to “plain language” drafting.

“Plain language” drafting is a idea that a reasonably educated person should be able to read and understand legal documents, rather than always having to hire a lawyer to sort through obscure specialized words and convoluted phrasing.  I am in favour of plain language drafting, and I consider it good news that federal legislative drafters are being guided by those principles.  Along the same line, I am in favour of the idea of using “must” to convey an imperative, since that is in accord with how most people understand the word.

What is concerning is that this shift is not well known among lawyers.  I only found out because I asked Department of Justice lawyers why a bill before Parliament said “must” rather than “shall”.  Such a shift deserves to be better publicized.  If this shift is not understood, lawyers, being very suspicious of change, will think that the use of a different word was intended to express a different meaning.

This leads me to recommend that the Department of Justice 1) publicize more widely the adoption of plain language drafting for legislation, and 2) change the Interpretation Act so that it embraces the word “must” as being imperative.