First and foremost, I've been saying for several years now, what Markos would have been saying if Perry wasn't unfortunately right (i.e., Kos has no clue what it means to be libertarian). A left-libertarian party is the only way the Dems are going to survive, because the electorate soundly rejects their two cores of power, the Soft Socialists (Kos, the Netroots, and Russ Feingold) and the Communitarians (Hillary, John Kerry, etc.) The latter have structural problems with being elected (and their outright rejection of liberty issues hurts them from the starting gate), and the former are dead in the water, because the Reagan Coalition was set up to fight these guys from Day One. The "Progressives" don't have any trouble getting their message out… the electorate hears it loud and clear, and rejects it outright for the semi-authoritarian pseudo-utopian claptrap that it is.
Going a step beyond Perry, Kos, on the other hand, cannot distinguish that there is a fundamental difference between positive and negative liberty. In other words, there is "freedom from" and "freedom for," and Kos is insensitive to the fairly drastic results of orienting oneself in one or the other direction. (Three guesses which orientation appeals more to the Democrats, and the first fifty don't count.) And to make the matter worse, he seems to posit that positive and negative liberty are unproblematically compatible.
That is a bozo no-no error that any freshman college student reading The Republic should be able to avoid.
In other words, Kos fails to walk the walk, because he has no clue how to talk the talk.