Pre-emptive war,is it ethical?

http://www.thepublicdiscourse.com/2018/02/21033/

“The third criterion, of right intention, looks forward in time. Assuming there is just cause, the morally sound intention of the statesman, and the citizen, must be the preservation or restoration of an enduring peace. It cannot be to take advantage of the weakness of an enemy in order to seize territory and secure other political objectives.”