Richard Posner just wrote one of those "read the whole thing" essays in TNR. And it's the clearest and most persuasive theoretical grounding of recent Democratic economic policies that I've seen.
It's dense in a few places, but he generally lays out pretty clearly the logic of things like the fiscal stimulus, policies that increase wages, and public investment. The essay doesn't say so explicitly, but it also illustrates the fundamental errors of Mark Sanford-style "tighten your belt" macroeconomics.
The logic of Posner's essay also strikes at the very heart of trickle-down economics. I know that economists don't take trickle-down to be a rigorous theory or anything. But I think the basic idea has a lingering hold on the minds of elected officials. At the least, it helps justify in people's minds why concentrations of wealth (estate tax) and income (tax cuts for rich) are good policy rather than things that should trigger pitchforked mobs.
Posner's essay, by contrast, spells out the basic Keynesian idea that "trickle-up" is a much sounder policy. And, as it turns out, this type of trickle-up, multiplier-seeking policy approach is exactly what the stimulus adopts. The essay also illustrates (by describing Keynes in plain English) why the various federal banking interventions were important -- namely, to produce the stability needed to stop people from hoarding.
Anyway, if you're an "interested amateur" like me, you'll enjoy it.
[UPDATE 2:35 PM: I should have made this more clear -- so thanks to Adam in the comments. Posner is one of the most important Chicago School figures of the 20th Century. Currently a federal judge, he was law-and-econish before it was cool. Accordingly, this essay is roughly equivalent to Glenn Beck embracing ACORN because "they help poor people." Or maybe Mr. Burns opening a public hospital. Or the Kagan family joining MoveOn.]