Cheney's dishonor

Over the last couple of days there has been a lot of indignant commentary like this:

The former vice president, the man who imported torture into the American constitutional system, failed to capture bin Laden, invaded a country under false pretenses, allowed the Afghanistan campaign to disintegrate, and added $5 trillion to the next generation's debt burden, is attacking a sitting president on a day he announces a critical military strategy in front of his troops.

It is, again, a breathtaking piece of dishonor from this bitter, angry man.

What's puzzling about it is that I don't quite understand why the mere act of "attacking a sitting president" should be considered so dishonorable. People seem to think there's some unwritten rule that says that former Presidents and Vice Presidents shouldn't weigh in on partisan political issues, but even if this is an unwritten rule, I fail to see what the benefit of it is, or why it's such a bad thing to break it. Certainly I wouldn't have had any problems if Bill Clinton decided to go into attack-dog mode on George W. Bush when he was president--in fact, I probably would have welcomed it.

Just to be clear, Cheney really is a dishonorable man. But this is the case not because he chooses to criticize the President contra some nicety of beltway decorum, but because he has done and believes in morally reprehensible things.