Yes he lied. Yes the Liberals lied. Blame the people who voted for him. They believed Liberal lies yet again.  Just like Albertans believed Conservative lies for 40 years and are paying for it now because they didn't plan prudently for the vagaries of the oil commodity cycle. 
Everyone lies including politicians. The trick is to measure and judge who lies least and if they lie what is the purpose. 
Trudeau abandonment of this pledge is the worst kind of lie. It's for political expediency and highlights once again that Liberals are corrupt at heart and cannot be trusted. Canadians have lost an opportunity for democratic modernization that they clearly voted for at election time.  Flanagan is right one this one. It will not be forgiven by progrsseive voters.  It's handing the Conservatives a big wedge. Big mistake.