Clever men explain why a ceasefire in Ukraine would not be a good idea. It would enable Russia to re-arm. (Ukraine is constantly being armed by America without need for a ceasefire.)
To me the war looks like one that neither side can win. If one side can win it I think that side is Russia, by sheer size of her armed forces.
Had the two warring sides made peace in 1915 the civilised world would have been saved. Or at the end of 1917, when Lord Lansdowne wrote his letter.
A German invasion of Poland might have been avoided had Britain not given Poland a guarantee in 1939, but this is very speculative and Beck was utterly stubborn and inflexible.
After the fall of France in 1940 Britain might have listened to what peace overtures Hitler had to make, as Halifax advised, but much better (for France and the Low Countries especially) not to have gone to war the previous year.
In 1955 the USA and Adenauer should have accepted Khrushchev's proposal for a united, democratic, neutral Germany, which would have freed East Germany from Communism, hugely benefited Germany and ended the cold war.
But once wars and cold wars start emotions become involved.
Lord Home, who accompanied Chamberlain to Munich in 1938, told me that as Prime Minister he would have used the hydrogen bomb if he thought Britain in immediate danger of attack from Russia 'because in that situation emotions become involved'.