It’s not clear to me what the question really means, and why it’s being “asked”. Mr Brooks answers it as though the real question is, “Could one party (to a first approximation of ‘one party’) unilaterally shut the Internet down?”, whether that might be done officially, maliciously, or otherwise. To that question, the answer is certainly “No.”
One interesting thing about Mr Brooks’s answer here is that it flies in the face of his answer in part 1, where he puts a lot of power in the hands of the U.S. government. But he’s correct here, not there: even the U.S. government could not shut the Internet down — though it certainly could interfere with it severely, simply because of how much Internet service and infrastructure sits in the United States. Many key sites could be shut down, including key ISPs and other services. The effects would, I believe, go well beyond the boundaries of the U.S., and would certainly have “strong effects [...] on a worldwide basis.”
Of course, should that happen, the rest of the world would quickly respond and replace those services. The disruption would be short-lived.
The difficulty of shutting things down can be demonstrated by the situation in China, where a number of attempts have been made to block access within China, as I noted the other day, to various services from outside that the government considers unsuitable for their citizens. But the fact is that Chinese Internet users have been able to get around those restrictions, by using satellite services, by taking advantage of proxy servers, and through other techniques. A country could certainly shut down service within its borders, and could make it a criminal action to bypass the restrictions... but the restrictions would be bypassed nevertheless.
Indeed, attempts to shut down various specific activities on the Internet have also failed. For better or worse, gambling, cyber-stalking, child pornography, misuse of copyrighted material, theft, scams, and everything else you can imagine continue on the Internet, despite efforts to stop them — just as is the case in the non-cyber world. Caveat user.
But another spin on the question goes more toward the old science-fiction scenarios. What if computers became too powerful? What if the Internet became a threat to people, and we collectively decided to shut it down to protect the human race. Not one party, unilaterally, but a general agreement... say, a significant majority vote in the U.N., with unanimous consent of the Security Council. Could we shut it down then?
I think the answer to that is also “No.” Not for the science-fiction reason that the computers themselves would prevent it (see part 2, “Could the net become self-aware?”), but for the more mundane, straightforward reason that contrary elements within our population would keep it going. The technology to run the Internet is out there, and it’s readily and inexpensively available. It’s not the “rocket science” that it once was.
The apple has been eaten.