Upon further consideration of the one of the original questions regarding jurisdiction, I understand that there is good reason to claim jurisdiction over marriage falls to the Provinces in Canada under the rubrick of "civil law" (Section 95 of the 1867 BNA).
While that is nominally the case, I think the governmental history of this subject provides a justified case for the Federal government's legislative initiative in this area.
1. Quebec's marriage law was the first to be struck down a couple of years ago. The Quebec Court of Appeals held their ruling in "abeyance" pending a response from the Provincial Legislature (i.e. the so-called 'National Assembly').
2. BC's marriage law was the next to go down - for exactly the same legal reasoning. The BC Court of Appeals held their ruling in "abeyance" pending a response from the Provincial Legislature.
It is to be noted that neither the Quebec nor BC's legislature made any move in any way shape or form to address the issue.
3. Ontario's marriage law was the next to go down - for exactly the same legal reasoning. The Ontario Court of Appeals let their ruling stand - which effectively threw the Ontario marriage law into the garbage and leaves Ontario without a marriage law of any kind.
4. Ontario, BC and Quebec Legislatures proved that they were unwilling or unable to address the issue. According to the law, there was no legal and valid marriage law in any of these three provinces.
On this basis, the Federal government moved to address a vacuum. It was considered the consensus legal opinion that each and every Provincial marriage law in Canada was due to be struck down, one by one as the cases arose. In the face of complete non-action on the part of the Provinces to whom such jurisdiction may be presumed to belong, non-action may constitute deriliction and justify Federal action on that account.
Prior to the Federal legislation to be tabled, there has been ample opportunity for the Provinces to legislate a new marriage law. All were apparently unwilling or unable to do so, including Klein who prefered to play political grandstanding games by mentioning Section 38 of the 1982 Constitution Act (the infamous Notwithstanding Clause).
On this basis, I believe the Federal government is completely justified in tabling legislation in this area. Provincial incompetance made it necessary.