The ‘blockage’ of BRP Sierra Madre in the South China Sea: revisiting the concept of pacific blockade in the modern era

Abstract

The South China Sea dispute has generated a series of confrontations between China and the Philippines, including China’s efforts to impede Philippine resupply missions to the grounded BRP Sierra Madre at Second Thomas Shoal. Although these incidents are frequently described as a ‘blockade’ in political and media discourse, blockade is a term of art under international law carrying specific legal requirements and consequences. This article critically evaluates whether the ‘blockage’ of the BRP Sierra Madre at Second Thomas Shoal qualifies as a blockade within the legal framework of jus in bello or whether it more closely resembles the historically contested concept of a pacific blockade—a peacetime measure that falls within grey-zone strategy. The analysis demonstrates that China’s conduct exhibits certain characteristics traditionally associated with blockade but falls short of satisfying several core legal requirements. In particular, the measures have been implemented in the absence of an armed conflict, have produced limited practical effects, and have not generated a level of harm sufficient to trigger the right of self-defence under contemporary jus ad bellum. The article argues that, while the concept of pacific blockade remains controversial, it provides a useful analytical framework for understanding coercive maritime measures that operate below the threshold of armed conflict. The BRP Sierra Madre incidents illustrate how states increasingly employ grey-zone tactics to advance strategic objectives while avoiding the legal consequences traditionally associated with war.