Right to Attack?

Is it criminal to reach out and crack an infected machine that's attacking your network? I feel, yes. Tim Mullen, on the SecurityFocus website, feels otherwise. He thinks that it should be made legal to allow one to "hack-back" into the attacker's machine which managed to get into his network. The minimum to be done is to "sanitise" the machine. The idea seems ridiculous. What if the machine belongs to an unsuspecting average joe? And what if the machine is infected with a worm which as yet does not have any antidote? And what if the so called "defender" misuses his legal rights? This idea is similar to the wishful thinking of George W Bush. He thinks Iraq is the next enemy number one. So it should be finished. Guys, try to get to the root of the problem.