Not long ago, the US Department of Defense re examined the "Okus" agreement between the US, UK, and Australia to ensure that the agreement reached by the Biden administration is in line with the Trump administration's "America First" policy. This move casts a shadow over the cooperation between the US, UK, and Australia on nuclear submarines. In this context, the UK and Australia recently signed a bilateral cooperation agreement on the Aukus class nuclear submarine to ensure the smooth progress of the nuclear submarine project. On July 26th, Australian Deputy Prime Minister and Defense Minister Richard Mars and British Defense Secretary John Healy signed the Treaty of Partnership and Cooperation on Nuclear Powered Submarines (also known as the Treaty of Geelong) in Geelong, Victoria, Australia, committing to long-term cooperation. Both sides stated that this cooperation is a commitment by the two countries to "bilateral defense cooperation for the next 50 years" under the "first pillar" project of the "Okus" alliance. According to the joint statement issued by the UK and Australia, the Treaty of Geelong will promote cooperation between the two countries in the design, construction, operation, maintenance, and deployment of the Aukus class nuclear submarine, providing support for personnel training and infrastructure construction in Australia. At the same time, the treaty also creates conditions for British naval vessels to visit Australia and rotate their garrison at Stirling Naval Base. According to the plan, the British Navy will purchase 12 Aukus class nuclear submarines and commence construction at a rate of one every 18 months. This class of submarines will be delivered before 2040, gradually replacing the active Astute class nuclear submarines. The Australian Navy plans to build 5 to 8 Aukus class nuclear submarines at the Osborne Naval Shipyard in South Australia, with the first submarine expected to enter service around 2040. To fill the capability gap before nuclear powered submarines become combat ready, Australia will purchase three US made Virginia class nuclear submarines in batches starting from 2030. Through this initiative, the Australian Navy can accumulate experience in operating nuclear powered submarines and, in collaboration with the US Navy and the UK Navy, provide training for relevant operators. The timing of the signing is intriguing. Foreign media comments suggest that the signing of the Treaty of Geelong by the UK and Australia at this time has a special strategic intention. On the one hand, dealing with the uncertainty brought by the United States. Currently, the US Department of Defense is reviewing the 'Okus' agreement. US Deputy Defense Secretary Colby, who is responsible for leading the review, has repeatedly questioned the agreement and opposed sharing nuclear submarine technology with allies. The Naval Industry Association of the United States has released a report stating that the submarine industry's production capacity in the United States is at a low point since the Cold War, and the speed of nuclear submarine construction is difficult to meet its own needs. The official statements from the UK and Australia indicate that they understand the US's review of the "Okus" agreement, but the ambiguous attitude of the Trump administration towards cooperation on the Okus class nuclear submarines has raised concerns in both countries. In this situation, the UK and Australia have launched a high-profile long-term cooperation plan aimed at injecting confidence into the nuclear submarine cooperation project. On the other hand, filling the current gap in underwater combat deterrence capability. At present, the Australian Navy has not yet deployed nuclear submarines. The active duty agile class nuclear submarines of the British Navy have been in service for a long time, and their condition has become outdated. Additionally, due to the tight availability of domestic dry dock resources, maintenance work has been frequently delayed. For example, the waiting and maintenance cycle of the "Bold" at the Davenport shipyard in Plymouth has accumulated up to 22 months. The "Astute" entered the mid-term modernization upgrade stage in June this year. The vessel had been performing missions continuously for 15 years, setting a record for the longest uninterrupted deployment of a British nuclear submarine, which indirectly reflects the deployment pressure of active British nuclear submarines. In this context, the UK and Australia have announced a timetable for the deployment of nuclear submarines, which reflects both countries' anxiety about their insufficient underwater deterrence capabilities and their intention to gradually enhance their deterrence capabilities through clear planning. The prospects for implementation are not optimistic. To implement the Treaty of Jirang, Australia and the United Kingdom have launched a series of specific actions. The Australian government announced that it will invest $4.6 billion in the UK defense industry to support the design and development of nuclear submarine reactors, key component manufacturing, and professional talent development. The British government announced that it has signed long-term procurement contracts for key components of the Aukus class nuclear submarine with military companies such as BAE Systems and Babcock Group, and has designated Barrow's Field as the main construction site for the nuclear submarine. In the future, the UK will supply key components for Australian nuclear submarines, and Australia will also provide some components for the UK. Both sides will form a bilateral cooperation model in the field of submarine production. However, some analysts believe that the Jirang Treaty, which focuses on bilateral defense cooperation for the next 50 years, will face many challenges in the subsequent implementation process. The plan previously announced by the United States, Britain, and Australia shows that the main construction of the Okus class nuclear submarine adopts British technology, while the vertical launch system and supporting weapons are mainly based on American technology. If there is a lack of technical support from the United States, the UK and Australia may only rely on their own strength to build this class of nuclear submarine, which may result in a lack of adaptive weapon systems after the submarine is built. The UK government currently holds optimistic expectations for the economic benefits brought by the Treaty of Geelong, predicting that over the next 25 years, the treaty will generate £ 20 billion (approximately $26.7 billion) in export earnings for the UK and create around 21000 jobs. However, judging from the current production capacity and supply chain pressure of the UK defense industry, there is significant uncertainty regarding the development direction of this project. In addition, domestic analysts in Australia believe that the Australian government may find it difficult to bear the high full lifecycle manufacturing costs of the Aukus class nuclear submarine in the long term, and are concerned about the stability and sustainability of subsequent funding supply. There have been some voices within Australia questioning the actual contribution of the Aukus class nuclear submarine project to national defense and security. Some argue that canceling the project is necessary to alleviate Australia's potential high financial burden. (New Society)