Think for a moment about what would happen if a foreign power launched a military attack calculated to destroy billions of dollars' worth of U.S. property - but without causing any injuries or deaths.
It would be an attack and retaliation would be swift and devastating, right?
Such attacks occur with regularity in cyberspace. U.S. officials say the latest involved Chinese hackers stealing sensitive data from dozens of Pentagon computers used to store weapons secrets.
Experts have warned for some time that the Chinese had developed a sophisticated cyber-espionage system. During the past few years they have used it successfully and repeatedly.
Yet - at least to judge by U.S. government statements - there has been no retaliation in kind.
Members of Congress ought to be asking that question. If the reason is that U.S. officials fear a cyberspace exchange that could leave our computer networks in shambles, then shame on us for not being as prepared to deal with online warfare as we are to handle a missile strike.
Again, Congress needs to get an answer to the question.