I'm a couple of days late picking up on this, so I apologize. But CBS's "Public Eye" online feature, which performs an ombudsman-like function for the network, had this post from the network's well regarded Pentagon correspondent David Martin explaining why, at the request of the military, he spiked a story about how the U.S. was trying to counteract the impact of IED's in Iraq.
You can agree or disagree with his reasoning -- and Martin makes it clear it was no easy call. But this is an enlightening case in that:
a) it effectively refutes the charge from some quarters that media outlets are always in a rush to publish and broadcast in wartime without regard for the impact on our troops.
b) it reinforces the idea that media outlets are constantly self-censoring for a variety of reasons without people screaming bloody murder about violating the sanctity of the First Amendment.