"The Prime Minister had no choice but to call for a cooling off period which is just as legitimate as calling for a coalition."

The prorogue procedure has never been used as a device to rescue a leader from a non-confidence vote in parliament. It's original function was to terminate a session of parliament when there was no longer a reason for it to sit, ie. all the bills presented in the throne speech had been passed and there was no outstanding house business to attend to. Harper has set a precedent which is a blatant abuse of parliamentary procedure and it will eventually come back to bite him in the ass.