Ultimately, all the decisions will be made by the debates commissioner himself. However, given the criteria that was established, a party leader would have to meet two of the three. First, being elected to the House under the party that he or she is leading, or having a member there; second, running candidates in 90% of all electoral districts; and third, having a sufficient chance to have a member elected to the House, given ongoing polling and public context.
On May 16th, 2019. See this statement in context.