In a brilliant piece yesterday, Paul Krugman gives voice to a phenomenon that I, too have noticed lately, to wit, that rightwing commentators, pundits and bloggers (Patterico's Pontifications, I'm looking at you!) can't tell the difference between a valid, albiet brutializing, policy argument, and an "ad hominem" argument where you just call someone a name.  Paul, you have the floor:

Greg Sargent takes us to Paul Ryan’s latest speech, in which Ryan expresses outrage over what President Obama is saying:

Just last week, the President told a crowd in North Carolina that Republicans are in favor of, quote, “dirtier air, dirtier water, and less people with health insurance.” Can you think of a pettier way to describe sincere disagreements between the two parties on regulation and health care?

Just for the record: why is this petty? Why is it anything but a literal description of GOP proposals to weaken environmental regulation and repeal the Affordable Care Act?

I mean, to the extent that the GOP has a coherent case on environmental regulation, it is that the economic payoff from weaker regulation would more than compensate for the dirtier air and water. Is anyone really claiming that less regulation won’t mean more pollution?

And Republicans have not proposed anything that would make up for the loss of the measures in the ACA that would lead to more people being insured. Let me also point out that whatever else you think of it, Romneycare — which is essentially the same as the ACA — clearly has sharply reduced the number of uninsured people in Massachusetts.

So Ryan is outraged,outraged, that Obama is offering a wholly accurate description of his party’s platform.

Let me add that this illustrates a point that many commenters here don’t seem to get: criticism of policy proposals is not the same thing as ad hominem attacks. If I say that Paul Ryan’s mother was a hamster and his father smelt of elderberries, that’s ad hominem. If I say that his plan would hurt millions of people and that he’s not being honest about the numbers, that’s harsh, but not ad hominem.

And you really have to be somewhat awed when people who routinely accuse Obama of being a socialist get all weepy over him saying that eliminating protections against pollution would lead to more pollution.

Emphasis mine.  Touche, Paul.