Ship raiding was once a common practice across much of archipelagic Southeast Asia, a region that encompasses modern-day Indonesia, Malaysia, and the Philippines, as well as several smaller states and outlying islands. Sanctioned by local rulers as a way to exact taxes on maritime trade, this raiding became illegitimate only when it was outlawed by the increasingly powerful Western powers in the late 19th century. Today, however, many of the region's states lack the ability to adequately govern their sprawling territorial seas. The massive flow of trade through these waters has allowed such practices to persist, providing funds for militant and organized crime groups alike, though the extent of piracy is limited compared to antiquity. One region with particularly high threats to maritime security is what is referred to as the tri-border area — the Celebes and Sulu seas and the surrounding coastal areas.