This is indeed the critical issue.
Regardless of the decision of the SCC, Mr. Harper and company are free to craft a new law, and they certainly have a history of creating new criminal laws.
To my mind question becomes how can Mr. Harper spin the law to his best advantage given an upcoming election, and the negative brand image they are creating for Mr. Trudeau.
1] If the court says the law is fine, then Mr. Harper will probably do nothing.
2] If the court gives a strange split decision compromise that is difficult to understand then all sides will claim a partial victory in the press. It will run the news cycle, and things will stay pretty much as they are.
3] If the court strikes down the law then Mr. Harper can play politics with virtually everyone on this board. The number of scenarios is really quite vast.
He could leak a document proposing a very Draconian law as replacement, wait for Mr. Trudeau to take the bait, and then attack Trudeau, brand him an evil pot smoking whoremonger to the voting public, and then bring out the real law he plans for the election.
I would expect in that case that the men will be the target of arrest under a new law.
I could go on and on with possible scenarios but they are totally my speculation and would be better in the politics forum (which I stay well clear of).
With respect to FemmeFatale and Jillian's comment, keep in mind this entire case was really instigated not by SPOC and others working in the industry but by Alan Young.
Mr. Young is an extraordinarily talented lawyer and lawyer professor. Straight out of school he clerked at the Supreme Court and his abilities are beyond a doubt. But in the same way some professors need to publish in various journals Mr. Young brings court cases.
He was instrumental in the changing of the laws regarding medical marijuana and then took up the cause of prostitution. He needs to have a cause that is somewhat salacious, clients that cannot afford the million dollars to take a case to the Supreme Court and most importantly, a case that will garner lots of press attention. The prostitution laws fit the bill perfectly.