Paul Krugman has a very interesting piece on Milton Friedman in the current New York Review of Books (not yet available online). Krugman praises Friedman's work as a positive economist, especially his demonstration that inflation and unemployment are not inversely correlated over the long run -- Friedman successfully predicted stagflation. Krugman notes that real-world trials discredited Friedman's claims for the power of steady-as-she-goes monetarism but concludes that overall Friedman's reputation as a giant on the order of (and in opposition to) Keynes is largely deserved. At the same time, Krugman criticizes Friedman's accomplishments as a popularizer and public intellectual. The arguments Friedman made for deregulation were not derived from Friedman's academic work and, in some instances, Krugman says, downright dishonest.
Although I share Krugman's views on the merits of Friedman's brand of laissez-faire, I want to put in a word in tepid defense of Friedman and indeed, of Krugman himself. Krugman's complaint sounds to me a bit like Laura Ingraham's contention that (liberal) celebrities who have earned their fame through their talent in entertainment should not opine about public issues but should instead "shut up and sing." One difference, I suppose, is that when Danny Glover, Susan Sarandon or the Dixie Chicks make policy proposals, most reasonably well-informed observers understand that they are using a platform that they were given for one purpose to promote issues on which they have no special expertise. By contrast, one might think that when Friedman, or for that matter, Krugman, writes a popular article about economics, the public will assume that it is thoroughly grounded in his technical expertise in economics, but like the actors and musicians, Friedman, Krugman and other scholars who also write for a popular audience (like yours truly) will sometimes use their expertise to support positions they favor mostly out of an ideological commitment. So the experts writing in this mode could actually be thought to be more dangerous than the celebrities speaking out on political issues.
But surely the conclusion cannot be that therefore anyone with serious expertise in a field should refrain from commenting on issues of public concern for fear that his or her views will be given too much weight. Instead, I think Krugman is probably best read to say that in writing for a lay audience, scholars can dumb down their arguments but shouldn't slant them. That's a sound prescription, but I doubt that those on the other side of any contentious issue will tend to see the resulting necessary over-simplifications as the result of a good-faith effort to popularize. At least that's the upshot of the nasty email I sometimes receive from some of my most conservative readers.