In war, there is inevitably going to be casualties that aren’t actual military targets.

That being said, I see a difference between taking out a nuclear scientist by means of a car bomb (which, in this case, would be to target the scientist specifically, but there’s no guarantee you can avoid harming an innocent) and waiting until the nuclear scientist enters a mosque for worship, then blow up said mosque (in which case an innocent person is guaranteed to die).

Obviously, if military action involves targeting specific people, such action should be as direct to the person as possible. It may be more difficult to accomplish, but if successful, it’s easier to defend yourself. Not so if you take the target down in a manner that results in more innocents than targets dying.

As for your scenarios, it seems to me that you have deliberately made the question fairly easy. In the first, what if it was generally known that nuclear scientists employed in the Iranian program were considered legitimate targets but the specific warning was not given? In the second, what if we don’t destroy the 3 nearby towns?

In either case, what if the attack is done by means of a car bomb or sniper’s bullet rather then a J-dam?

There is an important element here in the classification of killing in war - whether terrorism or not…

It is the difference between “discriminate” or “unavoidable” killing of civilians (where the killing is perhaps unavoidable because of proximity to a legitimate military target, or has been minimised by warnings of an impending attack) and “indiscriminate” or “intentional” killing (where the killing is avoidable, or undertaken with the intent of killing civilians, or without regard for the likelihood of killing civilians).

Now if I were to apply that difference to the Iranian scenario you are debating then I might come up with something like this -

1. Warn the scientists and others that undertaking activities that aid and promote the development of nuclear weapons could result in their deaths as legitimate military targets; then three days later bomb the place. Legitimate military action.

2. Warn no one, bomb the sites and the three
nearby towns out of existence. Terrorism.