For once I'm actually using a blog post as inspiration.
The post in question is titled "Shock and Awe without El Kabong". To summarize, it mentions a new missile being developed by Boeing which has the ability to generate a directed EMP effect - allowing it to neatly fry any electronic devices in a target as the missile flies past. The post continues to point out that such technology could be used to disable defenses while greatly limiting collateral damage.
Certainly, I'm happy to see it - improvements in precision weapons and nonlethal weapons make it easier for me to do my job while avoiding civilian deaths. That said, I'd also like to point out that this is far from a perfect solution. Granted, I think the author of the original blog post probably knows that, given the caveats that were included along with the proposed additional uses, but it's worth emphasizing that this, like every other technological advancement in history, can only change the nature of war so much.
One of these problems is the ability to defend against this missile's attack. There are some things which by their very nature will not be easily protected - building a Faraday cage around an antenna tends to make the antenna stop working. However, there's a lot more that can be isolated either with such devices or by building them that much deeper underground (and the blog post in question specifically calls out "provided they have not moved things underground" as one of its caveats). Even if the only recourse is to carefully switch your defense stations between "offline, useless, shielded" and "online, useful, unprotected", that's still more options than you get when your defense stations are smoking craters.
There are also some things that can't be effectively attacked with such technology. A rifle-wielding infantryman may wind up in trouble if he loses communications, night vision, or other electronic assists. He still has the capability to pose a threat, though, and many military technologies are designed with manual backups specifically so that they can continue to pose a threat even if something breaks. The Internet is another example. I've read the original blog post two or three times now and I still have no idea why the author thinks frying Wikileaks servers is plausible - or why he thinks that would do any good. Given the proliferation of mirrors, backups, and additional routers and paths, keeping anything off the air by hitting its storage media or communications links is the next best thing to impossible - at best, it would require a massive intelligence effort to find all of those things, followed by the political will to engage in quite a bit of "collateral damage" to mirror sites and archives that serve other sites as well as the one you were targeting. (Granted, "provided we can pinpoint servers" is the caveat listed with that idea, so I think the author understands that the idea isn't exactly a sure thing. Still, I think such a brief phrase vastly understates the difficulty of that task.) The same idea applies to using it to counter cyber operations - pinpointing their sources in real time remains difficult (at least, to the best of my understanding).
Finally, collateral damage remains a possibility. I alluded to that above when I pointed out that some servers run things we like along with things we don't like. One of the other possibilities here is that we could take out computerized regulatory/control systems for utilities, airports, or any number of other things - and that could have quite a few consequences, including death, for any noncombatants that really needed power or heat right then.
With all that said, I'll close out by acknowledging that I like the look of this new weapon myself. As I was saying above, there are manual backups - but the reason they are the backups is because they are less effective than the primary (electronic) methods. We still have to think about our tactics carefully and acknowledge that this won't save us from sometimes having to kill people - but this particular weapon gives us more nonlethal options than we had, and that's not a bad thing.