Sobering reading.
There's one thing to watch out for, though - as long as Beijing continues to have a strong trade relationship with USA that keeps a majority of urban China employed, you can bet that they're not going to disrupt that with an EMP attack against the US. They simply don't have strong enough internal security forces to deal with the worker uprising that would result when all the factory jobs disappeared when our economy collapsed.
If you see the CN government do what the Japanese government did 1925-1940 and progressively militarize (or otherwise internalize) the entire commercial work force, then at some point they'll be able to absorb the US trade-related job losses with small enough worker discomfort that they can bear to pull the plug. That's when to be worried and start grounding things.
Of course, Iran has no trade relationship with us, and if they successfully develop a fission bomb, they already have missiles sufficient to loft it over the eastern seaboard from international waters. After technology, the only deterrent we've got is the possibility of massive retaliation, and that would be difficult to justify without plenty of evidence that those scruffy guys on that freighter were supplied and financed by Iran.
See also: the majority of 9/11 hijackers were Saudi nationals, but we went to war with Afghanistan and Iraq over it.