Why did claimant states in the South China Sea (SCS) dispute, especially China, recently increase its militarization activities, in unprecedented ways that were relatively absent in the previous decades? Espousing an analytically eclectic explanation rather than using one single International Relations (IR) paradigm, this essay demonstrates three key exploratory arguments. First, the enduring Chinese military insecurity from American dominance in Southeast Asia has been recently amplified by the confluence of China’s economic rise, and more importantly, the power struggle in the current Xi Jinping-led regime. The article offers a domestic politics-oriented approach in explaining the strategic resolve of Beijing to militarize the disputed SCS region. Second, although many countries in the region uphold a ‘hedging foreign policy strategy’, which refers to their strategic engagement both with China and the USA, the Southeast Asian countries’ patterns of foreign policy behaviour and identity politics suggest that their longterm aspiration still relies on the USA as their primary security guarantor. Third, notwithstanding such perception of Southeast Asian states towards the USA, this article demonstrates that Washington’s long-term commitment of upholding its security guarantees to its Southeast Asian partners is hindered by the US interest to strategically engage with Beijing on broader issues of global governance.