OPINION | Indonesia's sea lanes give it overlooked leverage over China

This power dynamic has already been tested. In 2016 and 2017, Jakarta took a hard line on illegal fishing by Chinese vessels, detaining and scuttling captured Chinese vessels and, on one occasion, opening fire on a Chinese vessel. This all occurred in the part of the EEZ that China vaguely claims, waters that Indonesia calls the North Natuna Sea.

Despite this action, trade between the two countries kept rising. Indonesian exports to China were worth US$16.79 billion in 2016 and US$27.13 billion in 2018, while its imports from China increased by 50 percent in the same time period, from US$30.8 billion to US$45.84 billion.

The reason, clearly, was the unequivocal economic importance of continued access through Indonesian sea lanes. Ships going to Europe, the Middle East and Africa from China, and vice-versa, need to pass through the Malacca Strait, between Indonesia and Malaysia, or the Sunda, Makassar and Lombok straits within the Indonesian archipelago.