(They have nukes, but no reliable delivery system, BUT they have launched 3-stage rockets able to lift a "package" into low-earth orbit - they don't really need to aim it, anywhere over North America would do the trick....)
Red Dawn 2.0...
Their current object in orbit goes over Austin TX and Washington DC about 3 times a day. Of course its working its way east so only the DC area will be an option in a few more days.
EMP - what the media can’t talk about - no power for years is scary stuff.
http://en.wikipedia.org/wiki/Electromagnetic_pulse
That part would not surprise me....
Here is a link to a lengthy and frightening analysis of the EMP threat at Arutz Sheva. How close to, or far off, the mark is it? Beats me. However, even if we knew for a certainty that it would happen on April 10th, there would few steps, if any, to take now to prevent it; without at least relative certainty we seem unlikely to do anything useful. After such an attack? Maybe nuke Pyongyang, but that wouldn't help us much.
A small point: Korea is thirteen hours ahead of the U.S. East Coast. Since the warning for April 10th was directed to embassies in Pyongyang, it seems reasonable to assume that they referred to Korean time, suggesting that whatever they had in mind could occur on April 9th in Washington, D.C.