I do have to say this for Owen Smith.
He will not be voting against Article 50 because his constituents (what, all of them?) voted a certain way.
That would be a ridiculous position in a parliamentary system.
He will be voting against Article 50 because he judges that to be in the best interests of the country.
I do not agree with him, and were an MP than I should vote to repeal the European Communities Act even if there had never been a referendum.
But his position is eminently parliamentary.