Both Matt and Ezra have generally favorable responses to this Matt Miller piece, which argues, inter alia, that it's silly to call John Edwards a lefty populist, because his views would place him square in the Western European mainstream:
The centrepiece of Mr Edwards’ agenda is a call for universal health coverage. It sounds radical to American ears, perhaps. But Margaret Thatcher would have been chased from office in the UK if she had proposed a health plan as radically conservative as Mr Edwards’ – under which private doctors would supply the medicine, and years would still pass with millions of Americans uncovered.
Mr Edwards wants to lift the minimum wage substantially, and to boost wage subsidies for low-income work besides. But the outer limits of Mr Edwards’ ambition would leave low income work less generously compensated than the minimum wage and subsidy blend enacted by Britain’s New Labourites Tony Blair and Gordon Brown – arrangements Conservative party leader David Cameron says suit him just fine.
... I could go on, but you get the point. The fact that a Thatcher-Cameron-Buffet agenda can be hyped as “populist” says more about propaganda success and media norms than anything else.
Or maybe it says something about the actual-existing political spectrum in the United States of America, which is surely the relevant criteria to use when deciding whether to describe an American politician as "left" or "right." Similarly, if I were writing about the French elections, it would be silly for me to argue that the French press shouldn't label Sarkozy a "conservative" because after all, he's well to the left of Ronald Reagan or Bob Barr - since in the French context, which is the one that matters, he is right wing.
Obviously, progressives like to set Western Europe as the norm, and the United States as the exception, because they find Western Europe's political spectrum more congenial than ours; conservatives from time to time do the reverse, particularly when writing about France. But there's no independent standard that makes British or French socialism "normal," and U.S. libertarianism "absurdly to the right," as Ezra puts it. Especially since it's not particularly surprising that a collection of small densely-populated countries that share a common cultural, economic and political history over the last few hundred would gravitate toward one political and economic model, while a large, more-sparsely populated country with a very different political, cultural and economic history would gravitate toward a very different political and economic model. To assume that the former is the standard by which the normalcy of the latter should be judged, or vice versa, is to leap over a whole host of variables and arguments.
There is, of course, the liberal case that the U.S. would be just as left-wing as Europe if Republicans hadn't manipulated the system to skew the country away from its own preferences, but I've never found it terribly persuasive.