Several things; negotiation, arbitration, submission, and others, but there comes a point when war is unavoidable, and all that matters on either side is winning. It is a quality of the human race to fight. In history, probably more wars have been avoided than have been fought, but almost-wars are much more difficult to qualify or quantify.
The use of atomic weapons.
The Civil War killed more people than any other war.
In this sentence, a more correct version would be "the war is over" or "the war has ended."
World War I was not more horrific than any other war. Some would say World War II was though.
finished
he was in war
The War Between the States
War is the obtaining of a political goal by other than political means.
War is the obtaining of a political goal, by other than political means.
War is the obtaining of a political goal, by other than political means.
More Americans were lost than in any other war. And Americans were fighting Americans.
No, WWII remains the deadliest war.