From October 12 to 15, the navies of the United States, Japan, India and Australia held the second phase of the "Malabar 2021" maritime joint exercise in the bay of Bengal. Previously, the four countries also held their first offline summit in Washington. The recent move of the United States to establish a "small circle" in the Asia Pacific region has attracted the attention of the international community. Experts in relevant fields believe that the Biden government is trying to continue the framework of the "India Pacific strategy" and continuously institutionalize the cooperation among the four countries. A series of United States cliques to engage in closed and exclusive practices against other countries will lead to the intensification of national differentiation and confrontation in the Asia Pacific region and endanger regional security and stability. In March this year, less than two months after Biden became president of the United States, he was eager to hold the first leaders' meeting of the four countries online, reaffirmed his commitment to security cooperation among the four sides, and declared that he would cooperate in the production of Xinguan vaccine, key technologies, infrastructure investment and combating climate change. The convening of two summit meetings within six months shows the Biden government's eagerness to promote the "India Pacific strategy". The two summits focused on the epidemic situation, economy, ocean and regional situation, but on the whole, they were aimed at building the so-called "free and open Indo Pacific Regional Order" led by the United States. It is worth noting that security cooperation is the focus of the cooperation among the four countries. From the joint statement issued after the meeting, the four countries not only expressed the need to continue to strengthen cooperation in maritime security, counter-terrorism and cyber security, but also agreed to establish a working group on space and cyber security. In particular, on the issue of "maritime security", the four countries colluded to seriously express their concerns about the issues of the East China Sea and the South China Sea, and stressed the need to strengthen coordination on regional hot issues such as Afghanistan, Myanmar and North Korea. In fact, the security situation in the Asia Pacific has been relatively stable in the past few years, but after the emergence of the "four nation mechanism", extraterritorial forces have continuously intervened, the overall security and stability have been disturbed, and some hot issues may heat up again. Although the joint statement issued by the summit did not name and accuse China, it was insinuating and hyping the "China threat" between the lines. Based on the consideration of safeguarding its hegemony, the United States regards China as its strongest competitor, and even tries to win over some countries such as South Korea to join, seeking to unite "allies" to put pressure on China. The United States hopes to engage in great power competition with the help of the "India Pacific strategy", which is undoubtedly caused by the Cold War mentality. On the issue of regional security, the flirtation between the United States, Japan, India and Australia will only lead to tension in the region, which is not conducive to the effective improvement of maritime security, exacerbate the division of the Asia Pacific region and undermine peace and stability in the Asia Pacific region. Due to the differences among the four countries and the limited resources and capacity, the four countries have achieved few results in economic cooperation, and their cooperation in the field of infrastructure is also very exclusive, which is contrary to the trend of regional comprehensive economic partnership agreement reached in the Asia Pacific region in recent years and the prospect of higher-level economic cooperation. The "four nation mechanism" undermines regional economic cooperation and endangers regional security and stability. It will only be resisted and opposed by more Asia Pacific countries. In fact, the vast majority of countries in the Asia Pacific region seek cooperation rather than confrontation and are not interested in the "small circle" built by the United States with ulterior motives. As the spokesman of the Chinese Foreign Ministry said, any regional cooperation mechanism should not target or harm the interests of third parties, engage in closed and exclusive "small circles" against other countries, go against the trend of the times, run counter to the wishes of regional countries, be unpopular, and is doomed to fail. (outlook new era)