David Atkins writes some good stuff over on Digby's blog, but this post is...off. A complete counter would be necessarily very long, and so what follows is somewhat disjointed and skips across several arguments/points without joining them coherently (not actually sure that's possible, as much better philosophers than I have tried and failed)...
The very first "and most important" philosophical principle made is just wrong. We don't have a "principle of universality of morals". It would be really nice to think that, I guess, and he certainly points out a few moral choices that people in general and liberals in particular would certainly agree to, but part of the problem of moral issues is that they are not universal.
The second anyone starts off by arguing for something on a moral ground he is in trouble. Morals are not universal. Just because we nearly universally believe that slavery is wrong today, doesn't mean that position is really a universal moral. It could just be that rational arguments that justify slavery are non-existent.
Lots of people think that abortion is immoral, even plenty of "liberals"
who still believe it should be very legal and available. It is one of
the major problems in the abortion debate, particularly regarding why
the pro-choice side of things has a harder time gaining traction and
sustaining pressure compared to the anti-abortion side (they are most
definitely NOT pro-life).
Yes, I do recognize that at some level there is some moral/emotional framework underlying even rational ideas, and revealing that and trying to make a rational point absent it is troublesome...heck it got Socrates all and dead. And we can assume, as our moral framework, the Declaration of Independence. The Constitution respects that moral framework, and builds a system of government and law on top of it. That moral basis has some pretty broad acceptance, even outside the United States, but it isn't universal. It is very much our moral basis.
The second point has to do with weak nation states, particularly in the face of some global issues, and again, particularly climate change. This is an odd point, in that actually tends to run counter to the first argument.
I actually agree that global warming is one of those problems that we should but are unlikely to really do anything about. But part of the problem is that any interventionist push to solve this would necessarily trample on individuals' rights in such a way that the "universal moralist" from earlier would oppose. (China's Three Gorges Dam was good for reducing carbon, but it displaced lots of people, forcibly, and potentially created other environmental issues.) There is a reason that problems like these are difficult to solve, and while some idealists my imagine that the world can be just and good and fair, and that fighting global warming is a struggle of decent people against mindless corporations or something, it isn't that way. If you want to push to fight global warming, lots of people will suffer. If you don't, more people are likely to suffer, but you can't tell me that there is some way to universally weight the suffering of one group against another, pick one and say "for the greater good" without turning yourself into Grindelwald.