I think the American Prospect was most on point, when it noted,
...another thing about left-bashing “contrarianism”: It pays.Beinhart reportedly got a $600,000 signing deal for it, meaning either that he's smarter than the president, or else, what I'd think, being put up as a shill.
The Good Fight starts out with actually a good point, that liberals need to take lessons from earlier conflicts to think about winning the war on terror. Instead of fleshing out this idea, though, it gets into accusations that the Democratic party is in the hands of Michael Moore and such. Really it serves to generate more bad publicity for the left wing of the party than it actually adds to any debates. Generating more publicity than substance is something Beinhart is good at: he surreptitiously repudiated his support for the Iraq war, without providing any real convincing reason. While of course it's good to welcome anyone to "our side," I don't trust him to stay here, and I still think he embodies the worst of DLC triangulation.
Beinhart has been unusually active in the blogosphere and the editorial pages recently - one would suspect that his publishers are eager to get a return on their investment. I don't want to rain on his parade, but this book may apply less to the general public than it does to him.