As China increasingly integrates its coastguard into military exercises around Taiwan, the prospect of a quarantine scenario has gained growing attention. In such a scenario, Beijing could manufacture a crisis to justify the imposition of a quarantine around the island. For example, it might claim that all inbound and outbound shipments require inspection due to national-security concerns, such as alleged arms transfers or biological threats. The threat of an interruption to shipping is unnerving for an island that imports most of its fuel and much of its food.

A quarantine would aim to impose economic and psychological costs, erode public confidence in the Taiwanese Government and heighten social and political pressure. By disrupting trade and daily life while avoiding the overt aggression of a full military assault, such a campaign could foster an environment more conducive to coercive negotiation or unification on terms defined by the CCP.

With more than 150 large ocean-going vessels and more than 400 smaller boats, the CCG is well equipped to enforce such a quarantine. Probably operating in coordination with the PLA Navy, which would stand off at a distance, the CCG could try to divert commercial shipping and apply great pressure on Taiwan’s government. That would probably be accompanied by cyberattacks and disinformation campaigns designed to sow confusion, disrupt governance and further isolate Taiwan. If external support were insufficient or slow to materialise, the cumulative pressure could force Taipei to the negotiating table on Beijing’s terms.