Well, they are politicians.  That question is a subset of "Did anyone ever doubt that politicians are lying, craven opportunists".  
It's not that I am defending the Liberals, it is just the nature of the beast to attract people of this sort to the job.  The best of them try to tell as few lies as possible and show a little spine from time-to-time and that is about the best that ever happens.  Voters tolerate being lied to and together voters and the political system encourage taking the path of least political resistance.