Indonesia took a significant step toward global prohibition of nuclear-test explosions on Tuesday, by ratifying the Comprehensive Nuclear-Test-Ban Treaty (CTBT).

By doing so, Indonesia has increased the number of states that have ratified the Treaty to 156. Eight more from Annex II countries and the Treaty will come into force. Like Indonesia, these remaining eight are significant technology holders and thus their ratifications are mandatory for the Treaty to come into force — as was the case for Indonesia.

We have therefore made a strong declaration of commitment to a world without nuclear weapons. We have also made a timely contribution to the fortunes of the Treaty.

The timing of this move could not be more propitious. It came right after Indonesia, as Chair of ASEAN, successfully facilitated the conclusion of negotiations between ASEAN and Nuclear Weapon States...