Have Nuclear Weapons even escalated Conflict?
Yes they have and Events from the end of the 1950's to 1962 and again in 1983 prove that.
There had been a 15 year stand off between the West and Soviet Spheres since the end of WW2. There were even hostilities during times when one was very close to the other.
Khrushchev once described West Berlin as "a Bone stuck in his Throat" while there might have been the Blockade and then the Berlin Wall in response to all this.
America had a similar Attitude about Cuba after the Revolution and it became apparent they were Communists allied to the Soviets. There was the disastrous Bay of Pigs Fiasco, economic Warfare and even novel Ideas to depose Castro.
But neither led to whole Fleets facing each other off in the Atlantic like they did during the 1962 Crisis - which was caused by the very presence of Nuclear Weapons close to each others Territory.
"Able Archer" in 1983 might otherwise have been seen by the Soviets as just another NATO War Exercise were it not for what was thought to be a first Strike Nuclear Attack until further Scrutiny showed it wasn't. Were it not for the better Judgement shown by a Soviet Lieutenant that Day civilisation would have ended 43 years ago.
This wasn't the only time the Soviets saved the World from the Abyss.
During the 1962 Missile Crisis a Soviet Submarine was being pummeled by American Depth Charges and the Captain was on the brink of using a tactical Nuclear Weapon. The Crews Political Officer talked him down and prevented Nuclear War.
Many have suggested that Truman was wrong to use the Bomb against Japan.
It could also be argued that the Soviets would have forced Emperor Hirohito to sue for unconditional Surrender after they smashed the Japanese Armies in Manchuria and Mongolia. Japan had been hoping for a conditional Surrender via Moscow in the months before and had never faced the Soviet Army in Battle.
They very rapidly lost all the Territory they had on the north eastern Asian Mainland and it was obvious the Soviets weren't going to act as intermediaries.
So the use of the Bomb might have been unnecessary - even though the first Attack was before the Soviet Declaration of War on Tokyo. This is because their Invasion of Manchuko took months to prepare and Stalin had pledged a War on Japan as long ago as Yalta in February 1945, long before he knew about American Nuclear Weapons.
So Truman might have begun a 45 year Spiral that could very quickly have gone into apocalyptic free fall.
Do Nuclear Weapons guarantee Peace .....?
No they don't......
Within a couple of years of their use on Japan Nuclear Weapons did not deter the Soviet Union from their blockade of Berlin. Neither did they prevent North Korea - with Soviet and Chinese Support - from invading the South. They did nothing to stop the Warsaw Pact clampdown on the Protests in Poland and Hungary in 1956 and did not dissuade North Vietnam from pursuing their Aims - again, with Soviet and Chinese Support - in Indochina against Saigon, the French and Americans. The same applied in Czechoslovakia in 1968, the various Cold War Crises of the 1970's and the Soviets War in Afghanistan.
Indeed, it could be argued that they nearly caused World War several times during all this ....
General MacArthur wanted to use the Bomb on North Korea and China but, thankfully, was prevented from doing so by President Truman.
The Cuban Missile Crisis pushed the World to the Brink by mutually provoking both America and the Soviet Union. Khrushchev wanted Missiles in Cuba because America had them in Turkey, both of which would have rendered any early warning Systems useless by their Proximity, and there were People in X-Com who were prepared to launch a full scale pre-emptive Attack on Cuba in response to the Weapons that were there.
Nixon wanted to use them on North Vietnam but cooler Heads prevailed.
More recently, the UK might have had the Bomb but it did not prevent the Argentine invasion of the Falkland Islands, even though Polaris could very easily have been launched from a Submarine off the Coast of Buenos Aries.
It was the prospect of a Nuclear Strike by the West created during the Exercise "Able Archer" in 1983 which nearly prompted a full Soviet Response.
Both India and Pakistan have Nuclear Weapons, but their continuing and occasionally violent Spat about the disputed Kashmir Region has never ended.
Both China and the US have the Bomb but neither have prevented the other in the continuing Jostle over Taiwan. Nukes did nothing to prevent the provocatively unthinkable recently when the Speaker of the US Congress Nancy Pelosi crossed the diplomatic Line and recognised Taiwan as an independent country. The proverbial Third Rail in Sino-US Relations.
Israel now has Nuclear Weapons, but this has never prevented any incursions against them since, or the huge Iranian Response to their Assault last year (2025).
So it could be argued that the very existence of Nuclear Weapons might actually cause War and even the Doomsday Scenario. They induce a sense of Complacency which neglects other Solutions.
The Cold War started when Truman wanted to scare the Soviets by using a new Atomic Weapon in 1945, which merely hardened Attitudes and guaranteed that Moscow would begin work on their own Bomb rather than a Spirit of Conciliation between the former WW2 Allies.
It wasn't until the Missile Crisis of 1962 when the potential use of Nuclear Weapons became horribly apparent that work started to be rid of them with the first in a succession of Treaties governing them.