I think nuclear arms have proven themselves as a means of defending. There would have been conflict between east & west by now had there not been a nuclear stalemate.
The nuclear attack on Japan saved countless lives, forcing them into surrender and abruptly ending their killing & torture adventures.
The first sentence is supposition since no one have had the slightest inclination to attack us, ignoring of course the attack by Putin in buying the damaging Brexit result!
The last sentence only a partial truth, the bombs will have been a factor, but not the major one.
After defeating the Kwantung Army so devastatingly the Japanese were as it says here More affected by the Soviet entry into the war, by two Atomic attacks which were in fact relative pin pricks comapared to the preceding Fire raids using incendiaries
https://www.japantimes.co.jp/opinion/2016/08/06/commentary/japan-surrender-world-war-ii/#.W9oF4eKYS00
"
In February 1945, the Japanese military conducted a survey that concluded that Japan could not win the war. But they were not squeamish about the suffering of the Japanese public — more than 60 Japanese cities were subjected to extensive firebombing in 1945, displacing, maiming and killing several hundred thousand civilians. Military leaders could not contemplate the ignominy of surrender, so they compelled their nation to continue fighting a war that was already lost, subjecting the Japanese to horrific suffering that they could have ended far sooner.
Historian Tsuyoshi Hasegawa, in his 2005 book “Racing the Enemy,” provides compelling evidence that the Pacific War ended due to the entry of the Soviets, not the atomic bombings. Having tasted defeat at the hands of the Soviets twice in the late 1930s in Manchurian border clashes, the generals knew that the new front meant further resistance was futile."
And I would add that the Soviets had defeated the Kwantung Army in just one week!
"
Tsuyoshi Hasegawa's research has led him to conclude that the atomic bombings were not the principal reason for Japan's capitulation. He argues that Japan's leaders were impacted more by the swift and devastating Soviet victories on the mainland in the week following
Joseph Stalin's August 8 declaration of war because the Japanese strategy to protect the home islands was designed to fend off an Allied invasion from the south, and left virtually no spare troops to counter a Soviet threat from the north. Furthermore, the Japanese could no longer hope to achieve a negotiated peace with the Allies by using the Soviet Union as a mediator with the Soviet declaration of war. This, according to Hasegawa, amounted to a "strategic bankruptcy" for the Japanese and forced their message of surrender on August 15, 1945.
[36][15] Others with similar views include the
Battlefield series documentary,
[2][10] among others, though all, including Hasegawa, state that the surrender was not due to any single factor or single event.
But by all means keep believing in the Fiction you are so fond of it's the very stuff and soul of Brexit thinking.