While others have already commented on Adam Dodek's argument that judges should never enter politics after leaving the bench, I'll offer a couple of observations of my own having to do largely with our perceptions of politics (and the need not to let them override democratic principles).
Dodek's concerns arise largely out of attacks launched by the Cons against Carol Baird Ellan based on some of her past decisions. But it's worth asking whether the problem lies primarily with Baird Ellan's candidacy or the Cons' standard in evaluating it - and how best to address that problem once it's identified.
Let's start by noting that it's absolutely true that judges occupying that role must decide - and must be seen to decide - each case based on the law rather than based on any external consideration, including future political implications. (In this respect, I fully agree with Dodek.)
That said, I'd attach the duty at its highest to the judicial role alone - not indefinitely to the person who occupies it, but who may come to find other priorities worth pursuing.
On that front, I'd hope nobody would look at the career path of, say, Louise Arbour and argue that her experience on the bench should have limited her ability to later work on human rights or international conflict resolution - being the areas where she found an opportunity to apply her skills and experience in the service of the greater public good.
Indeed, to the extent we value a judicial temperament, it's a trait we should be looking for in other areas of society as well - including the political arena, where a sense of fairness or objectivity is all too often lacking.
In Baird Ellan's case, there's of course more of a clash between talking points and the realities of judicial experience - which include decisions which can be manipulated for political gain by a sufficiently unscrupulous opponent. Such is the system as it stands now, and so it will remain until we set a higher standard in politics.
But while Dodek's answer is to keep lowest-common-denominator politics away from anybody associated with the bench, I don't see the value in shutting out well-informed citizens who could go a long way toward setting that higher standard. And if the goal of ensuring better decision-making in multiple branches of government requires a bit more work to defend the judiciary in the meantime, then we should be prepared to put in the effort.