The biggest hurdle facing the Liberals is relevance. They finished with less than 20% in two thirds of the seats. Outside of a few urban and suburban seats in Winnipeg and Vancouver and Goodale's seat the Liberals were neck and neck with the Green's west of Ontario. Outside of Montreal, the situation is even worse in Quebec.
The Liberals are not going to be able to build from the grassroots up for the simple reason that in great swaths of the country there is no grassroots from which foster a rebirth.
If the Liberals are going to make a comeback, it will have to be orchestrated from the top not from the bottom. Furthermore, such a rebirth is only possible within the next couple of years. The Canadian population feels no loyalty to the "natural governing party" whatsoever. The Liberals have for so long stood for nothing that no body stands with them now. If the Liberals do not reinvent themselves and quick, they will loose what urban seats they have left to the NDP and what suburban seats they have to the Conservatives.
So, what can be done? The Liberals need to take advantage of the only thing they have going for them, viz., a residual interest in them from the nation's media. They must pursue policies that draw headlines and fuel editorials. That means support for legalizing marijuana and euthanasia. That means supporting mandatory voting. That means abandoning support for equity, asymmetrical federalism and collective rights. That means calls to abolish the senate, the monarchy and a call for much more representative House. The Liberals can not longer afford be the party that defends the status quo. They have to be the one challenging it.
Of course, such a strategy will can only work if the Liberals abandon the notion that they can use the media to reach Canadians. The bulk of the silly, insubstantive, unoffensive, small ball talking points that Liberals trotted out in opposition interested no one least of all the media. Very few ever reached your average Canadian accept maybe as the objects of ridicule in various editorial columns. As the third party, things will be even worse. No, the Liberals have to develop coherent positions and arguments and serve as the liberal columnists and opinion makers that Canada simply does not have. Their goal should be to dominate the national discussion for long as possible.