Posner quotes Keynes:
Posner, if you read his book on Failure of Capitalism, is more of Keynesian than most liberal Keynesians.
Keynes warned President Roosevelt in an open letter of December 31, 1933, about trying to combine far-reaching reform with recovery from an economic depression. He wote that
even wise and necessary Reform may, in some respects, impede and complicate Recovery. For it will upset the confidence of the business world and weaken their existing motives to action, before you have had time to put other motives in their place...And it will confuse the thought and aim of yourself and your administration by giving you too much to think about all at once.
The passage that I have italicized deserves particular emphasis (though Keynes's warning that "it will confuse the thought and aim of yourself and your administration by giving you too much to think about all at once" is equally timely) because of the strange turn that the debate over health reform has taken in recent days.