An individual killing another person, and a government's military killing foreign soldiers is only a "morphological coincidence"? And that doesn't strike you as gaslighting?

I understand that the ban on killing needn't be absolute. Exceptions can be made to laws. But regulating/legalizing wars with laws that permit certain military actions makes for a mighty large loophole. The loophole is so large it's liable to cause cognitive dissonance because of the clash between domestic and international/political standards. Legalistic or diplomatic gaslighting lessens that dissonance.

The US Constitution is being pragmatic and instrumental, outlawing murder at home while permitting it abroad to protect the nation's tranquility. The question there isn't about the moral status of killing; rather, certain killing is deemed useful as a means to a greater end, while other kinds of killing prevent us from achieving that goal (national peace).

Is tranquility the highest good, though?