Lincoln could either cave into the secessionists and let the country fall apart or else take a stand, maybe a purely formal stand, in an effort to keep the country from losing its capital. That was what Buchanan left him, and war was what the secessionists gave him.
So you must think that war was forced on King George 90 years earlier. George could either cave to the colonials and see his empire fall apart or else take a stand etc.
Or hold it together by force and brutality like the Soviet Union.