She immediately goes for the nuclear option. Let alone the fact that the anti-trust measure should not ever be considered with a free market motive (not only is a government fix to a government-caused problem, it's also an anti-competitive measure used by rent seekers), she does not consider alternatives that could be considered reasonable (maybe) under certain conditions of, say, natural monopoly (i.e. rate regulation) where a genuine public interest is affected (as opposed to what passed off as a public interest in Nebbia v New York).
I generally agree with this critique. However, I think Libby's arguments - even to the extent I disagree - show something important about why a left-libertarian coalition that would replace the longstanding right-libertarian coalition is both possible and likely.** While Libby hardly speaks for the Left as a whole, and is in general one of the more libertarian-friendly liberals around, much of what she writes in her post is fairly typical of many liberals that I know.
So, if I disagree with the arguments and believe the arguments are fairly typical liberal critiques of capitalism, why do I think Libby's post demonstrates the possibility for a left-libertarian coalition? The answer is that the principal underlying her arguments is an essentially libertarian principal - the principal that economic competition is desirable, and that more competition is inherently good.
This is a far cry from the socialism and fetish for central planning that once animated the American Left. In those days, the Left viewed competition as an essentially zero-sum game in which only government intervention could create progress. Libby's post demonstrates that those days, for the most part, are gone. The Left has, by and large (though by no means completely), moved from trying to plan against competition to trying to plan for competition (even if we think those plans will do more harm than good, the fact is that the goal is to enhance private competition). Devotees of Hayek will understand the immense importance of this distinction.
Simply put, the ends of contemporary liberalism/progressivism have in large part been restored to their classically liberal roots, even if we libertarians may think that their preferred means are not particularly consistent with classical liberalism.
I would also add that there is one point Libby makes which libertarians would do well to internalize - and that is the creeping destruction of choice that results from monopolization (particularly where that monopolization occurs as a result of government protectionism). I think Libby is correct in suggesting that this can be as big a threat to liberty as direct government action - one need only look at the warrantless wiretapping program to understand this.
If we accept the dangers inherent in a symbiotic relationship between government and corporate monopolies, then libertarians in large part need to have a shift in priorities. While we can maintain our opposition to the social welfare state, the fact is that the corporate welfare state (including anti-competitive regulations, subsidies, and, notably, the military-industrial complex) must become our biggest priority in the field of economic policy. After all, a welfare recipient doing the government's bidding is a lot less of a threat to liberty than a corporate rent-seeker doing the government's bidding, particularly when that rent-seeker has access to all sorts of records and communications that the government would typically be prohibited from obtaining without a warrant.
In fighting the corporate welfare state, especially to the extent it includes government contracting, I would hope libertarians could all agree that the political Left is a more natural ally than the political Right.
**As always, when I refer to a right-libertarian or left-libertarian coalition, I refer only to libertarians in the broadest sense, with the full recognition that libertarian purists would never align with either coalition.