近期，朝鲜半岛紧张持续升温，美韩与朝鲜都指责对方为引起局势紧张的源头。美国军事部门自年初就宣称朝鲜随时会进行第七次核试验，并将此作为既成事实来应对。8月底至今，美韩、美日韩5年来首次相继重启“乙支自由之盾”、“警戒风暴”、反潜演习等联合军演，且规模大幅增加，美军“里根”号核动力航母、B-1B战略轰炸机等战略资产5年多首次飞抵朝鲜半岛。近日，美韩高层多次表态会对朝鲜可能的核试验采取前所未有的措施。G20峰会期间，美日韩三国峰会首次发表联合声明，宣布三国共同强化对朝威慑能力。朝核问题在举世瞩目的中美元首巴厘岛会晤中也是重要议题。同期，朝鲜也不遑多让，颁布核政策法令，大幅降低核使用门槛，密集进行导弹试验和空中演训，朝韩军机一度在空中对峙，朝鲜导弹飞跃日本上空并首次落入“北方界线”（NLL）以南区域。

朝核问题自年初开始就逐步进入紧张周期，近期加速发酵，其背后动因值得探究。

首先，美国解决朝核问题的动力不足，借朝核问题做局的态势明显。2019年美朝河内峰会破裂后，特朗普政府和其后的拜登政府都无意在朝核问题上消耗资源，而是一手坚持拉拢盟国共同对朝施压、制裁，另一手则低调应对朝鲜的导弹试射举动，避免朝核危机发酵扩大，实际上奉行一种变相的“战略忍耐”政策。

近期，随着美国在乌克兰问题上取得阶段性优势，民主党在中期选举中表现出色，拜登政府在朝核问题上的调门明显变高。但美国的政策重点并非解决朝核问题，而是通过炒作朝核议题来捆绑日韩，加大对华围堵。近期美韩、美日韩军事合作大幅推进，美国在东北亚的军事投入明显增加，远超出了应对朝核的需要，反而是针对中国的态势明显。G20峰会期间，素来强调只针对朝鲜的美日韩三国首脑会谈发表联合声明，大篇幅提及台湾、南海、经济安全、印太秩序等议题，针对中国的内容远超朝鲜。拜登、沙利文等美方高层多次对中国施压，表示若朝鲜继续提升核导能力，美国将扩大在东北亚的军事部署。可以预见，在朝核“契机”下，美韩、美韩日联合军演将继续扩大，美国有可能加大在东北亚的战略资产部署，扩大延伸威慑，追加部署萨德导弹防御系统。在朝核问题中，美国作为绝对优势的一方，不去触碰半岛和平机制和安全保障等根本问题，却一味选择对朝高压手段，这无异于抱薪救火，更加刺激朝鲜加速核导开发。

其次，朝核危机加剧也与朝鲜自身逻辑有关。平壤承认，目前因遭遇全面制裁和孤立而承受了经济上的巨大困难。美韩日军事存在的大幅增强，也加剧了朝鲜的安全压力，现有僵滞局面长期延续只会愈加被动。朝鲜迫切需要以攻为守，通过提升核导能力和降低核使用门槛来谋求对美韩同盟的不对称均衡，迫使各方正视其诉求，摆脱核武提升、综合国力竞争却日益被动的结构性困境。

朝鲜持续提升核导能力所导致的前景可能有三。一是招致更为严重的国际制裁。安理会已有的多个制裁决议已经明确，朝鲜继续发展核武会导致制裁升级，但目前美俄、中美关系的现状可能影响这一前景。二是通过大幅提升核能力迫使美韩妥协。在拜登政府和韩国保守政府目前的政策基调下，这一前景可能性不大。三是刺激大国在朝核问题上的分歧，加剧东北亚新冷战态势，也即重新回到冷战时期中俄朝对美日韩的状况。这一前景将帮助朝鲜脱离冷战后长期受制于核问题的被动孤立局面。俄乌战争后，朝鲜一直力挺俄罗斯的逻辑就在于此。近期，美国指责朝鲜向俄出口武器，俄罗斯总统普京则批评韩国向乌克兰提供武器，半岛双方卷入新冷战的姿态明显。朝鲜明显期望的是第三种前景。

其三，韩国、日本的态度也助长了朝核问题的升级。日本与美国一样将朝核问题作为围堵中国的一种策略，其立场毋庸多言。韩国作为半岛问题重要的当事方，其立场的微妙调整颇值得玩味。文在寅政府重视朝鲜半岛和平，强调半岛双方的自主性，不希望半岛成为大国竞争的前沿，因此注重对朝怀柔，避免刺激朝鲜。尹锡悦政府将美韩同盟作为外交政策基础，强调对朝遏制，不断推动美韩同盟安全合作加深，加大对朝延伸威慑。本来，韩国的常规武器优势加上美国的延伸威慑，在朝核问题上已经形成一种占优的均衡。韩国继续加大这种优势，朝鲜无疑只能继续升级核武以自保。

从目前有关各方在朝核问题上的立场来看，各方都有做局、作势的需要，甚至形成了一种特别的“默契”，因此朝核危机升级在所难免。

与历次朝核危机一样，目前有关各方看似剑拔弩张，实则高举轻放，都不希望真的发生冲突。然而，在近期美韩叫嚣对朝“先发制人”、朝鲜大幅降低核武使用门槛（“核先发制人”）的情况下，双方由误判导致冲突甚至上升为核战争的风险在加大。近日朝韩军机在空中对峙、朝鲜射导触发日韩部分地区的防空警报等表明了这种风险。半岛真的发生冲突，显然不符合各方的利益。但即使各方仍能避免冲突，东北亚新冷战态势加剧、核扩散风险上升以及半岛双方卷入大国博弈，对各方来说也恐非吉兆。

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.