I finished reading "Little Brother" about twenty minutes ago, so it's all still sort of bouncing around in my head, but here are some of my initial thoughts. Spoilers ahead.
I love the way Doctorow weaves in lessons about security online and computer technology, but I love even more the way he weaves in crystal-clear explanations for why it's not just criminals who have something to fear from increased security systems. The central narrative of the book is driven by one massive, glaring example of this, but throughout, subsequent moments of people getting screwed over or punished for nothing more than living in a high-security area are weaved in every few pages. And, as the book makes dramatically clear, it's not like it ever did anything to catch the terrorists -- I can't recall a single instance of terrorism being uncovered, or even showing up, in the book beyond the attacks that drive the plot in the first place.
He does a great job of touring through the injustice that PATRIOT Act style security can bring down on the citizenry by dragging the main character through it, more than once, but I think the more important lesson he imparts, after making it visceral through Marcus's experiences, is showing the many, many other people dragged through the same systems, for little or no reason (he makes the point near the end that it's mostly because they're brown) and left in there longer and more painfully, all in the interests of stopping those terrorists they didn't catch.
I'm not sure I totally believe the ending, though. I mean, I'm glad the book had a happy ending, and I guess I can conceive of the possibility of a governor kicking the federal government out of his or her state. But maybe it's just that I'm too over-acclimated to our current, tragically inept system, but it just doesn't ring true to me.
Still, the lessons in this book are valuable and important, and I'm glad they're getting into the hands of our nation's children.