debellation

Etymology
Borrowed from, from.

Noun

 * 1)  The act of conquering or subjugation in war.
 * 2)  The annihilation of a sovereign state through its complete destruction in a war.

Usage notes
In contrast to an ordinary surrender or defeat, debellation is a condition in which a defeat is so total that the vanquished state no longer functions as an institution and no further resistance is possible, and the state may therefore be said to have become legally extinct.