Rex Murphy wrote the following in Saturday's Globe and Mail:

Now we hear that, actually, the law he passed changed nothing. I like parliamentary expert Ned Franks's description of that law as meaning “a fixed election date if necessary, but not necessarily a fixed election date,” which the good Queen's professor supplemented with the observation that “it's what in the trade they call a ‘pious hope.' ”

From my Wednesday CTV.ca feature:

Queens University's Ned Franks agrees, telling CTV.ca the bill creates more of a political problem for Harper than a legal or constitutional one in calling an early election. He agreed one could think of the law as 'a fixed election date if necessary, but not necessarily a fixed election date' -- to paraphrase former prime minister William Lyon Mackenzie King. "It's what in the trade they call a 'pious hope' -- in other words, a promise that can be broken with impunity if you think you can get away with it," he said of the act.