The increasing tensions in the Asia-Pacific region is primarily being driven by China's continuing and rising aggressive incursions into the exclusive territories and economic zones of neighboring sovereign countries, including the Philippines, Vietnam, Malaysia, Brunei, Taiwan, and Japan. Beijing does not honor international arbitration rulings and rejects even the UNCLOS or the UN Convention on the Law of the Seas.
A quick look at China's evolving foreign policies can give us a glimpse of the philosophy of China’s current aggressive stance under Xi Jinping. In August of 2004, the CCP or the Chinese Communist Party then General Secretary Hu Jintao, declared that China would relentlessly pursue its independent foreign policy of alleged peaceful development "stressing the need for a peaceful and stable international environment especially among China's neighbors". Under Hu, China's foreign policies were anchored on the philosophies of "mutually beneficial cooperation" and "common development". This has always been China's core foreign policy since the founding of the Peoples' Republic in 1949. Today, Xi is reversing the tide and abandoning the traditional policies of Beijing.
The evolution had a twist in 2007, when Qin Gang, China's Foreign Relations mouthpiece, responded with an 8-point China policy, as an answer to then US Vice President Dick Cheney's criticism of the increasing militarization of China which was seen by the Western Bloc as a threat to the peace and stability in Asia. This was, however, balanced in 2011 when then China's Foreign Minister Yang Jieche declared Beijing's "integrated approach" to push for China's total development. Xi Jinping, upon assuming power, started as peacemaker. In the 6th Plenum of the CCP in 2016, Xi, as general secretary, proclaimed Beijing's policy of transparency in decision-making processes to improve China's image abroad.
What followed, however, were complete contradictions of What Xi proclaimed. On June 13, 2021, the Group of Seven (G7), composed of the world's strongest democracies; the US, UK, France, Germany, Canada, Italy, and Japan, openly criticized China for its series of abuses in geopolitics, including Beijing's alleged systematic destruction of the democracy in Hong Kong, repeated military threats against Taiwan, mistreatment of the Muslim Uyghur minority, unfair trade practices, lack of transparency concerning the origin of COVID-19 inside China, and its unreasonable and illegal belligerence against the Philippines in the South China Sea. All these were rejected by China and Beijing continues to talk nicely but act in the opposite direction. Its foreign policies then could be called a policy of blatant deceptions.
The current aggressions in the South China Sea and its incursions into the territories of neighboring states as well as its shameless claims over resources in our exclusive maritime zones are the palpable evidence that Beijing cannot be trusted as a neighbor. Its unreasonable and illegal use of its self-serving so-called Nine-Dash Line and later amended unilaterally into Ten-Dash Line are conclusive evidence that China does not respect international law. It does not honor duly-constituted international tribunals on arbitration, much less show the faintest respect to any arbitral awards. China is using superior economic and military power to bully the Philippines and Taiwan, as well as its former ally, Vietnam.
The ASEAN member nations are split regarding relations with China. While the Philippines, Vietnam, Malaysia, and Brunei are openly against China, Beijing has invested a lot in Cambodia, Myanmar, Laos, Indonesia, Thailand, and Singapore which then are cold to the Philippines' efforts to have ASEAN condemn China's illegal actuations in the West Philippine Sea.
The bottom line is that it is China which is causing tension in the region and the smaller states are just trying to stand up to a huge bully in Beijing.