689 is a leading Supreme Court of Canada decision on the Trade and Commerce power under section 91(2) of the Constitution Act, 1867.

To much of the public's surprise the Court struck down a provincial statute regulating the marketing of eggs.

238 which held that provincial law that has an incidental effect on other provinces is still valid.

The Court held that even though there was no direct evidence showing that there was extraprovincial effect of the provincial law, the potential effect was sufficient to find the law ultra vires.

The Court found that control of imports was essential to the provincial legislative scheme even though the law made no distinction between eggs produced inside or outside of the province.