A while back I called this the "presumption of ideological orthogonality"

Paul Krugman writes about some very strange perceptions of Keynesianism: "Pensions are Keynesian economics? Bloated defense budgets are Keynesian economics? Who knew? Even bank bailouts, whatever you think of them, have nothing to do with anything in the Keynesian model per se.

So what’s going on here?

I’m not the first person to notice this, but whenever you read conservatives trying to critique what they think the other side believes, you find them assuming that their opponents must be mirror images of themselves. The right believes that less government spending is always good, regardless of circumstances, so it assumes that the other side must always favor more government spending. The right says that deficits are always evil (unless they’re caused by tax cuts), so they assume that the center-left must favor deficits in all conditions."

The right and libertarians have some obvious examples of this lately, but I think it's probably a human thing more than anything else. It's similar to what I once called the "presumption of ideological orthogonality". I wrote:

"Classical liberalism" no longer means what it used to mean - it has become a synonym for libertarianism. All the differences of opinion between the classical liberals, and all liberals through the ages, are jettisoned and a libertarian core alone is maintained as legitimate.

This sort of "compression of Liberalism" inevitably leads to what you might call the "presumption of ideological orthogonality". Let me provide an example. I'm sure many of you have had someone run through the ten planks of the Communist manifesto for you and check off the several points of the list that we've adopted in the U.S.. The exercise (I suppose) is meant to be some sort of stunning revelation about how Communist we've become. But the argument falls flat. Why? Because it relies on this "presumption of ideological orthogonality". To be convinced that it says anything about the extent to which we're Communist, you have to believe that Communism shares no perspective at all in common with Liberalism. You have to assume that all ideologies are perfectly independent of each other, so that a check list is sufficient for determining how Communist one is. A similar example with fascism is the common claim that the fascists supported public works projects. What does this demonstrate other than that the fascists apparently agreed with a lot of Liberals on the value of the strategic use of public works projects? Why does this observation imply that Liberals who do support public works actually resemble fascists? Why can't it imply that fascists who do support public works are actually secretly Liberals (I don't believe that either, but it's telling that you never hear anyone draw that conclusion - why don't you?). The fact is, economic and political ideologies are not perfectly orthogonal. There are a lot of perspectives out there that support a progressive income tax. My support for a progressive income tax is integral to my Liberalism, which is grounded in my classical liberalism. This doesn't change because Marxists or fascists also support progressive income taxes for their own reasons.

It's extremely disconcerting to me that for a lot of smart people out there the options are apparently libertarianism and corporatist fascism, and that if you depart from libertarianism you "resemble fascism". Analytically, it's a laughable conclusion. But socially, it's disconcerting as well. One of the great things about Liberalism is that historically it has practiced what it preaches with regards to pluralism. Advocates of human liberty and representative government have always maintained disagreements on specific points and emphases. Liberalism is not a homogenizing perspective. It's deeply unfortunate that we've come to the point where departure from one brand of classical liberalism isn't recognized as another version of Liberalism, but an alien ideology."