I am a proud Canadian in moments like this.
The law in the US is going to be challenged sooner rather than later. You don't have to wait for the government to "decide" in their own time. The US has a law that recognizes the legality of marriages performed in Canada. Which makes sense, if someone has a Canadian wedding, they are still considered married in the US. So all it will take is a brave couple to get married here, and then sue the government to have it recognized.
That's how it started here. One couple found a loophole in the marriage legislation, so they were able to get married by having banns published in church, then took the government to court when they were prevented from registering the marriage. It is a wonderful story about how one (in this case, two) people were able to make a difference.