The problem is that the charge does not fit the crime.
When when some guy is running the streets killing people, and somebody decides to kill him to prevent more mayhem - that is not premeditated murder.
The Judge allowed only that charge. I see that as flawed. Therefore the whole trial is flawed.
“When when some guy is running the streets killing people, and somebody decides to kill him to prevent more mayhem...”
So, according to you, Roeder would have also been justified in killing a pharmacist or killing random women since one in four American women of child bearing age will have an abortion?
Quite the fanciful picture you paint above, just a shame that it does not, in any way, correspond to Roeder's premeditated murder of Tiller.