Ghost of a flea

Yes, with a significant caveat. The attacks will originate from an ISP through a bot-net, including innocent third-party hosts—never through something as obvious as say, gov.cn.

For example, let's say Russia wants to DDOS some US system. One of their dudes codes a script to attack the US target, and then tries to infect a wad of computers with it. Preferably ones belonging to civilians in a US ally—say Canada. Then on the given date/time the attack is unleashed.

Who does the US decide to go after? The majority of the attacking systems were Canadian, albeit acting on botnet instructions from a foreign source. But is that foreign source traceable back to the Russian government, or just some lone gunman geek with an axe to grind? Who gets the response? The fingerprints are not clear-cut, so the response will similarly be a digital one, not an LGB aimed at a building.

Read the article "The Dogs of Web War" in January's Air Force magazine, it has some interesting quotes from the Pentagon's cyber warriors. China, for instance, wages sophisticated peer-level web war pretty well every day:

In 2003, a barrage of attacks from China hit Pentagon systems. The incursions were notable enough to get their own temporary code name, Titan Rain.

...In February 2007, officials at Naval Network Warfare Command acknowledged that Chinese attacks had reached the level of a campaign-style, force-on-force engagement, according to Federal Computer Week.

...All of this is creating a level of frustration. As [JCS Vice-Chairman Gen. James E.] Cartwright characterized it, “The probing of our networks, day in, day out, has gotten to a point where it’s so egregious it actually cries and demands that we take some kind of action.”

Of course there is always this, from Col. Charles W. Williamson III, in May's Armed Forces Journal ("Why America needs a military botnet"):

"If the US is defending itself against an attack that originates from a computer which was co-opted by an attacker, then there are real questions about whether the owner of that computer is truly innocent. At the least, the owner may be culpably negligent, and that does not, in fairness or law, prevent America from defending itself if the harm is sufficiently grave."

So keep your virus scanner signatures up to date, or Uncle Sam may end up giving your infected PC The People's Elbow.