Robin Hanson of "Overcoming Bias" thinks "signalling theory" can tell us something about the left, particularly the wealthy, "post-materialist" left.
Signalling theory arises out of a paradox of game theory. It is often in our short-term self-interest to have a reputation for not always acting in our short-term self-interest. If people think my word is my bond (i.e., I will make sacrifices to fulfill my promises), then they will enter into transactions with me that they otherwise wouldn't and I'll be better off. If people think I am vengeful (i.e., I will make sacrifices to punish those who wrong me), they will avoid harming me when they otherwise would, and so on. From an evolutionary standpoint, the future benefit of having a reputation for doing such things is the explanation for why we have apparently unself-interested emotions in the first place. The trouble is that reputations for generosity, fair-dealing, vengefulness and so on are costly to acquire. So we are built (by generations of natural selection) with an aptitude for cheating: we try to get these reputations on the cheap. These mechanisms can be unconscious, and usually are, since if you can't fool yourself you are unlikely to fool anyone else. Other people are endowed by natural selection with a motive to pierce through my signalling strategies: I'm not.
Which is where politics comes in beautifully. Political opinions, at least in bourgeois democracies, don't cost us much, if anything. But they can signal (for instance) that we deeply care about the poor, a reputation it is useful to have, without requiring charitable contributions, which can put a dint in one's lifestyle (and therefore other possible status-seeking strategies). The right sees this, if the left does not, and calls on leftists to "do good at your own expense." That's Hanson's theory anyway.
Of course, a reputation for compassion is not the only kind of reputation that can be cheaply bought with political opinions. We, especially men, want a reputation for toughness and clear-headedness. We could get this by risking our bodies, but it is more convenient to get it by advocating muscular foreign policies. The left sees this, if the right does not: hence the "chicken hawk" argument which Dick Cheney and George W. Bush never liked very much: "Prove your manliness at your own risk."
Neither critique is strictly relevant to policy questions. A social program might still do more good than it offsets in charitable donations, even if advocating it provides cheap psychological benefits, and the same is true of a military intervention. But these critiques at least have the merit of dissolving the aura of virtue (whether soft or hard) that floats around arguments for "doing something".
Which gets me to Ignatieff, and the larger tradition of Pearsonian activism he has inherited. What bugs me about him is that he employs the signalling strategies of both the domestic left AND the international right, AND then leverages the contrarianness of doing both simultaneously into a reputation for "thoughtfulness." He's strong but sensitive. That would be appealing if Canada needed a boyfriend, but not if it is seeking a mere adviser to Her Majesty on matters pertaining to the federal government.