A definition of war
The classic definition of war is politics by another means.
Of course there are other ways to define war.
Usually it involves people from different cultures not really understanding the other cultures, like they will think like them, and react like them. How naive, but that seems to be what usually happens.
And then there are world wars, usually started by regional powers like Germany and Japan. That has happened, too.
And of course, most wars involve casualties, sometimes in the millions.
Now, I don't want to die because of somebody else's naive mistakes/good intentions. There are alternatives for the savvy leaders.