近期，朝鮮半島緊張持續升溫，美韓與朝鮮都指責對方為引起局勢緊張的源頭。美國軍事部門自年初就宣稱朝鮮隨時會進行第七次核試驗，並將此作為既成事實來應對。8月底至今，美韓、美日韓5年來首次相繼重啟“乙支自由之盾”、“警戒風暴”、反潛演習等聯合軍演，且規模大幅增加，美軍“里根”號核動力航母、B-1B戰略轟炸機等戰略資產5年多首次飛抵朝鮮半島。近日，美韓高層多次表態會對朝鮮可能的核試驗採取前所未有的措施。G20峰會期間，美日韓三國峰會首次發表聯合聲明，宣布三國共同強化對朝威懾能力。朝核問題在舉世矚目的中美元首巴厘島會晤中也是重要議題。同期，朝鮮也不遑多讓，頒佈核政策法令，大幅降低核使用門檻，密集進行導彈試驗和空中演訓，朝韓軍機一度在空中對峙，朝鮮導彈飛躍日本上空並首次落入“北方界線”（NLL）以南區域。

朝核問題自年初開始就逐步進入緊張周期，近期加速發酵，其背後動因值得探究。

首先，美國解決朝核問題的動力不足，借朝核問題做局的態勢明顯。2019年美朝河內峰會破裂後，特朗普政府和其後的拜登政府都無意在朝核問題上消耗資源，而是一手堅持拉攏盟國共同對朝施壓、制裁，另一手則低調應對朝鮮的導彈試射舉動，避免朝核危機發酵擴大，實際上奉行一種變相的“戰略忍耐”政策。

近期，隨着美國在烏克蘭問題上取得階段性優勢，民主黨在中期選舉中表現出色，拜登政府在朝核問題上的調門明顯變高。但美國的政策重點並非解決朝核問題，而是通過炒作朝核議題來捆綁日韓，加大對華圍堵。近期美韓、美日韓軍事合作大幅推進，美國在東北亞的軍事投入明顯增加，遠超出了應對朝核的需要，反而是針對中國的態勢明顯。G20峰會期間，素來強調只針對朝鮮的美日韓三國首腦會談發表聯合聲明，大篇幅提及台灣、南海、經濟安全、印太秩序等議題，針對中國的內容遠超朝鮮。拜登、沙利文等美方高層多次對中國施壓，表示若朝鮮繼續提升核導能力，美國將擴大在東北亞的軍事部署。可以預見，在朝核“契機”下，美韓、美韓日聯合軍演將繼續擴大，美國有可能加大在東北亞的戰略資產部署，擴大延伸威懾，追加部署薩德導彈防禦系統。在朝核問題中，美國作為絕對優勢的一方，不去觸碰半島和平機制和安全保障等根本問題，卻一味選擇對朝高壓手段，這無異於抱薪救火，更加刺激朝鮮加速核導開發。

其次，朝核危機加劇也與朝鮮自身邏輯有關。平壤承認，目前因遭遇全面制裁和孤立而承受了經濟上的巨大困難。美韓日軍事存在的大幅增強，也加劇了朝鮮的安全壓力，現有僵滯局面長期延續只會愈加被動。朝鮮迫切需要以攻為守，通過提升核導能力和降低核使用門檻來謀求對美韓同盟的不對稱均衡，迫使各方正視其訴求，擺脫核武提升、綜合國力競爭卻日益被動的結構性困境。

朝鮮持續提升核導能力所導致的前景可能有三。一是招致更為嚴重的國際制裁。安理會已有的多個制裁決議已經明確，朝鮮繼續發展核武會導致制裁升級，但目前美俄、中美關係的現狀可能影響這一前景。二是通過大幅提升核能力迫使美韓妥協。在拜登政府和韓國保守政府目前的政策基調下，這一前景可能性不大。三是刺激大國在朝核問題上的分歧，加劇東北亞新冷戰態勢，也即重新回到冷戰時期中俄朝對美日韓的狀況。這一前景將幫助朝鮮脫離冷戰後長期受制於核問題的被動孤立局面。俄烏戰爭後，朝鮮一直力挺俄羅斯的邏輯就在於此。近期，美國指責朝鮮向俄出口武器，俄羅斯總統普京則批評韓國向烏克蘭提供武器，半島雙方捲入新冷戰的姿態明顯。朝鮮明顯期望的是第三種前景。

其三，韓國、日本的態度也助長了朝核問題的升級。日本與美國一樣將朝核問題作為圍堵中國的一種策略，其立場毋庸多言。韓國作為半島問題重要的當事方，其立場的微妙調整頗值得玩味。文在寅政府重視朝鮮半島和平，強調半島雙方的自主性，不希望半島成為大國競爭的前沿，因此注重對朝懷柔，避免刺激朝鮮。尹錫悅政府將美韓同盟作為外交政策基礎，強調對朝遏制，不斷推動美韓同盟安全合作加深，加大對朝延伸威懾。本來，韓國的常規武器優勢加上美國的延伸威懾，在朝核問題上已經形成一種佔優的均衡。韓國繼續加大這種優勢，朝鮮無疑只能繼續升級核武以自保。

從目前有關各方在朝核問題上的立場來看，各方都有做局、作勢的需要，甚至形成了一種特別的“默契”，因此朝核危機升級在所難免。

與歷次朝核危機一樣，目前有關各方看似劍拔弩張，實則高舉輕放，都不希望真的發生衝突。然而，在近期美韓叫囂對朝“先發制人”、朝鮮大幅降低核武使用門檻（“核先發制人”）的情況下，雙方由誤判導致衝突甚至上升為核戰爭的風險在加大。近日朝韓軍機在空中對峙、朝鮮射導觸發日韓部分地區的防空警報等表明了這種風險。半島真的發生衝突，顯然不符合各方的利益。但即使各方仍能避免衝突，東北亞新冷戰態勢加劇、核擴散風險上升以及半島雙方捲入大國博弈，對各方來說也恐非吉兆。

Tensions on the Korean Peninsula have continued to rise recently, with the U.S. and DPRK blaming each other. The United States military has claimed since the beginning of the year that the Democratic People's Republic of Korea will conduct its seventh nuclear test at any time, and has acted as if this a fait accompli.At the end of August 2022, for the first time in five years, the U.S. and the Republic of Korea conducted joint military exercises, including operations called “Eulji Freedom Shield” and the “Storm of Vigilance.” Together with Japan, they have staged trilateral anti-submarine exercises at significant scale. A U.S. nuclear-powered aircraft carrier, the B-1B strategic bomber and other military assets have come to the region for the first time in more than five years.Recently, the top brass of U.S. and ROK stated that they would take unprecedented measures against a possible nuclear test by the DPRK. On the sidelines of the G20 summit, the U.S., Japan and ROK announced in their first joint statement that they would work together to strengthen their deterrence capabilities against the DPRK. The nuclear issue was also on the agenda of the China-U.S. summit in Bali, Indonesia, which attracted worldwide attention.The DPRK quickly responded with a nuclear policy decree that significantly lowered the threshold for the use of nuclear weapons. It conducted intensive missile tests and air drills, staged an air combat show of force against ROK military aircraft along the border and sent missiles flying over Japan and splashing down south of the Northern Limit Line (NLL) for the first time.

The DPRK nuclear issue has gradually entered a tense cycle since the beginning of the year and has worsened recently. The motives behind which are worth exploring.

First of all, the U.S. lacks motivation to resolve the issue and is clearly taking advantage of it. After the breakdown of the Hanoi summit in 2019, the Trump administration and the subsequent Biden administration had no intention of wasting resources on the DPRK nuclear issue but rather brought allies together to exert pressure and impose sanctions on the DPRK. They responded to the DPRK missile test launches in a low-profile manner to avoid an expansion that would only make things worse and actually exercised a sort of veiled “strategic patience.”With the U.S. gaining a stage advantage recently in Ukraine and the Democratic Party doing well in the midterm elections, the Biden administration's tone on the DPRK nuclear issue has heightened significantly. However, U.S. policy is not focused on resolving that issue, but only on hyping the issue to engage with Japan and the ROK and increase the siege against China.

Recent U.S.-ROK and U.S.-Japan-ROK military cooperation has advanced significantly, and the U.S. military investment in Northeast Asia has increased — far beyond what is needed to deal with the DPRK nuclear issue — all of which is apparently targeted against China. On the sidelines of the G20 summit, the U.S.-Japan-ROK summit, which has always emphasized that it is solely directed at the DPRK, issued its first joint statement mentioning Taiwan, the South China Sea, economic security and the Indo-Pacific order at length and targeting China far more than the DPRK.U.S. President Joe Biden, National Security Adviser Jake Sullivan and other senior U.S. officials have repeatedly pressured China, saying that the U.S. will expand its military deployment in Northeast Asia if the DPRK continues to upgrade its nuclear missile capabilities. It is foreseeable — using the excuse of the DPRK nuclear issue — that the U.S.-ROK and U.S.-ROK-Japan joint military exercises will continue to expand. The U.S. could increase its deployment of strategic assets in Northeast Asia, expanding and extending deterrence and deploying additional SAD missile defense systems.On the DPRK nuclear issue, the U.S., as the overwhelmingly dominant party, does not address fundamental issues such as the peace mechanism or security guarantees on the peninsula but simply chooses high-handed means against the DPRK, which is tantamount to trying to put out fire by adding more firewood. This will further stimulate the DPRK to accelerate its nuclear capabilities and missile development.

Second, the intensification of the DPRK nuclear crisis is related to the DPRK's own logic. Pyongyang acknowledges the enormous economic difficulties it is currently enduring as a result of the comprehensive sanctions and the isolation it has encountered. The significant increase in the U.S.-ROK-Japan military presence has also exacerbated security pressures on the DPRK. As the existing stalemate will only become more passive in the long run, the DPRK urgently needs to take up offense as defense and seek an asymmetric balance against the U.S.-ROK alliance by improving its strike capabilities and lowering the threshold for nuclear use to force all parties to face up to its demands and get rid of the structural dilemma of increasing nuclear weapons and growing passivity in the competition for composite national strength.

Prospects for the DPRK's continued upgrading of its nuclear missile capabilities are likely to be threefold:First is to invite more severe international sanctions. Multiple sanction resolutions by the UN Security Council have made clear that continued DPRK nuclear development will lead to an escalation of sanctions, but the current state of U.S. relations with Russia and China could affect this prospect.Second is to force the United States and the ROK to compromise by significantly increasing the DPRK's nuclear capabilities. This prospect is unlikely given the current policy of the Biden administration and the conservative ROK government.Another angle is stimulating disagreement between big powers over the nuclear issue and exacerbate a new cold war in Northeast Asia — that is, a return to the Cold War-era status of China, Russia and the DPRK versus the United States, Japan and the ROK. This prospect might help the DPRK break out of its long post-Cold War passive isolation with respect to the nuclear issue. This is the logic behind the continued DPRK support for Russia in the war in Ukraine.With the U.S. recently accusing the DPRK of exporting weapons to Russia and Russian President Vladimir Putin criticizing the ROK for supplying weapons to Ukraine, the possibility of the two sides of the peninsula becoming involved in a new cold war is obvious. The DPRK clearly expects the third prospect.Third, the attitude of the ROK and Japan has also contributed to the escalation of the DPRK nuclear issue. Japan, like the United States, uses the DPRK nuclear issue as part of a strategy to contain China, and its position goes without saying. 

As an important party to the peninsula issue, subtle adjustments in the ROK position is interesting.The Moon Jae-in administration said peace on the Korean Peninsula is important and emphasized the autonomy of both sides. It didn't want the peninsula to become a frontier for great-power competition. Thus it was conciliatory toward the north and wanted to avoid provoking it.But the Yoon Seok-yeol administration has made the U.S.-ROK alliance the basis of its foreign policy, emphasizing containment of the DPRK and constantly pushing for deeper security cooperation in the U.S.-ROK alliance and greater extended deterrence against the north. In fact, with its conventional weapons advantage, combined with extended U.S. deterrence, the Republic of Korea has obtained a dominant position against the DPRK. As the ROK continues to increase this advantage, the DPRK will undoubtedly have to continue to upgrade its nuclear weapons to protect itself.

The current positions of the parties involved in the DPRK nuclear issue show that they all have a need to exploit it, even forming a special tacit agreement. So an escalation of the nuclear crisis is inevitable.

As with all previous nuclear crises, the parties involved appear to be at war but are actually holding their heads above water and do not want a real conflict to occur. With the recent calls by the U.S. and ROK for preemptive strikes against the DPRK, however, and the DPRK's drastic lowering of the threshold for the use of nuclear weapons (“nuclear preemption”), the risk of a miscalculation by both sides leading to a conflict or even a nuclear war is on the rise.The recent air-to-air combat standoff on the border between the DPRK and ROK, as well as the DPRK's missile launches, which triggered air defense alerts in parts of Japan and the ROK, demonstrate that this risk is real. In the event of a conflict on the peninsula, this would clearly not be in the interests of all parties. And even if the parties manage to avoid conflict, the intensification of a new cold war in Northeast Asia, the rising risk of nuclear proliferation and the involvement of both sides of the peninsula in a great-power game do not bode well.