以下摘譯和摘錄四位西方專家的分析。

由於這是當下最火紅的國際政治議題，我就客串一下躺椅上的政論名嘴，略表淺見。

1.     如果普丁動用戰術核武，美、歐政府領袖會採取強硬和實質反擊。

2.     承上，普丁不會動用戰術核武。

我的推論理由如下：

A.    普丁沒有入侵烏克蘭的「正當性」，也就沒有在戰敗後動用戰術核武的正當性。

B.    如果美、歐領袖坐視普丁動用戰術核武，不予回應；則任何核子俱樂部會員，以後都將使用這種「先恫嚇，後執行」的戰略處處訛詐，時時訛詐。

C.    所以，基於「生存危機」而不是站在「道德高度」，美、歐政府領袖會強硬反擊任何動用戰術核武的政府或團體。

我相信普丁會考慮到以上這個邏輯。站在普丁立場，他已經了解到：俄國菁英和人民不會容忍缺乏「正當性」的戰爭影響到他們自己的生活和安全。如果他不找個漂亮或不太丟臉的台階下，讓美、歐聯軍把戰爭帶到俄國本土，他立馬就有步上胡笙或卡達菲後塵的可能。如果他能搭個差強人意的台階下，他可能混到72歲或75歲再以健康理由榮退。面對「生存危機」和「面子危機」的選擇，只有笨蛋才會以後者為優先選項。普丁的外號很多，「笨蛋」絕非其中之一。

西方專家的分析：

Mark F. Cancian：「如果俄國只在烏克蘭國境內使用核武，NATO應該不會以核武回應。NATO非常懼怕核戰被帶到自己國境內。同樣的，由於以上原因，我也不認為NATO會派遣傳統武力到烏國境內作戰，或攻擊俄國境內城市。」

J Andrés Gannon：「我認為NATO會以強大的傳統武力協助烏國光復從2014後失去的土地*。我不認為NATO會使用戰術核武反擊；因為它們不是NATO戰備中的強項，也不具有太高的戰略性優勢。」

* 此處沒有說清楚「光復從2014後失去的土地」是否包括克里米亞。再我看來，要普丁在目前放棄克里米亞，很可能逼著他狗急跳牆，玉石俱焚。 -- 卜凱

Ambassador (ret) Melvyn Levitsky：「我認為俄國動用核武的可能性非常低。

冷戰期間彼此心照不宣的『相互毀滅戰略禁忌』，在今天仍然適用；以致沒有一個核武國家會冒動用它的大不韙。即使俄國使用小型戰術性核武，其殺傷性會擴及到它目前佔領的宕倍士區域甚至俄國本土。

即使普丁有『狗急跳牆』的傾向，他的團伙中也會有人阻止他。」

Lasha Tchantouridzé：「我認為俄國很可能動用核武。但很可能不會在烏國境內。莫斯科有三個更方便的選項*：…」

* 這三個選項選項的內容及其戰略考量請見以下摘錄的原文。 -- 卜凱

What Happens If Putin Uses Nuclear Weapons? What The Experts Told Us

Harry Kazianis, 09/30/22

The press these days is mad about one question regarding the war in Ukraine: would Russian President Putin dare use nuclear weapons? And as crazy as this sounds, we will find out soon enough if the Russian leader is truly bluffing or not.

…

Our specific question for these experts: What happens if Putin uses nuclear weapons in Ukraine? Here is what they told 19FortyFive:

Mark F. Cancian, Senior Adviser, CSIS: “If the Russian use of nuclear weapons were confined to Ukraine, it is unlikely that NATO would support using nuclear weapons in response. The European nations would be terrified of escalation onto their territories, and President Biden has repeatedly signaled a reluctance to “start World War III.” Similarly, I doubt that NATO would use conventional forces either in Ukraine or against vulnerable Russian territory like Kaliningrad because of the same

…

J Andrés Gannon, Stanton Nuclear Security Fellow at the Council on Foreign Relations: “I expect NATO to engage in a strong conventional military response aimed at curtailing the Russian offensive and helping Ukraine regain control of territory lost since 2014. NATO is unlikely to use nuclear weapons because similarly-sized tactical nuclear weapons are not a strength of the Western arsenal, nor would they provide much strategic utility.

Conventional retaliation could try to escalate the conflict enough to impose significant costs on Russia, hoping to deter future nuclear use by them or anyone else, while not escalating so much that Russia feels they have nothing left to lose.

…

Ambassador (ret) Melvyn Levitsky, Professor of International Policy and Practice, Gerald R. Ford School of Public Policy, University of Michigan: “I believe the use of nuclear weapons by Russia is highly unlikely.

The Cold War doctrine of Mutual Assured Destruction, although not as explicitly stated as during the Cold War, continues to hold today to ensure that none of the nuclear powers would risk using nuclear weapons. Russia’s use of even a small tactical nuclear weapon makes no sense. Radiation from such use would affect Russia’s own troops in the Donbas region and spread to Russia itself.

There is a danger of the “caged tiger” syndrome in which Putin would try to use nuclear weapons out of self- or regime preservation, but I think that others in his group would intervene in such a case.

…

Lasha Tchantouridzé, Ph.D. Professor, the Graduate Programs in Diplomacy and IR Norwich University: “Russia is very likely to use a nuclear weapon in its current campaign, but it is unlikely to be done in Ukraine itself. Instead, Moscow may find a more convenient target in Europe.

The president of Russia has at least three options. One, Russia can resort to a high-altitude detonation. This way, it can disable much of Europe’s infrastructure, including Ukraine. Two, it can launch a cruise missile against a sparsely populated area in Europe, i. e. one of Germany’s great forests, a remote part of Sweden, etc. Three, it can deploy a nuclear device covertly to a less significant NATO city, causing thousands of casualties and blaming Americans. NATO cannot do much in any of these cases.

However, the United States will have a choice between a retaliation followed by many millions of casualties and an acceptance of whatever explanation Moscow may produce. The latter choice is much more likely for at least two main reasons: since 2008, Washington has largely accepted the Russian versions of events, and two, the American president is not likely to trade American cities to retaliate for an attack on an unknown European city the name of which most Americans cannot even pronounce.”