International relations scholars frequently classify the United Kingdom and the United States as quintessential ‘offshore balancers’, but an often-overlooked major island country also enters this category — Indonesia. As an offshore balancer, the rise of a regional hegemon will be a wake-up call for Indonesian foreign policy.
Offshore balancers often feel less urge to commit to continental power politics. They can enjoy the benefits of seclusion to focus on domestic development instead. Since the sea palisades them against invasions, offshore balancers require less formidable ground forces relative to continental powers. At the same time, large bodies of water make expansion on the continent more difficult.
There is one peril for which offshore balancers will firmly commit to continental security. A regional hegemon is the only type of rival strong enough to accumulate and project sufficient forces to subjugate or even conquer an offshore power. Once relieved from neighbouring rivals, a regional hegemon can focus on more faraway targets. As the dominating behemoth, it can mobilise all the continent’s resources at its leisure for distant endeavours. As such, ensuring that no regional hegemon arises is imperative for offshore balancers.
If Indonesia is an offshore balancer, we should witness distinguishable patterns of behaviour. Typically, Indonesia would feel little need to participate in continental power politics, thanks to seclusion from the continent by bodies of water. Safe from invasions, the country should maintain a relatively small military relative to its potential. But Jakarta would turn more assertive in the face of a could-be regional hegemon.
History suggests Indonesia behaves like an offshore balancer.
When Indonesia gained independence in 1949, Southeast Asia faced no significant hegemonic threat. China remained weak, and Vietnam was torn asunder by war. Jakarta could safely ignore continental conflicts and declare neutrality in the Cold War.
The regional balance shifted dramatically after Vietnam’s reunification in 1975 and its invasion of Cambodia in 1978. The growing Vietnamese threat pushed Jakarta to strengthen its military capabilities and improve combat readiness. It assumed a leading position within ASEAN, helping transform it into a coalition to contain the expansion of communism in Southeast Asia. It also moved to mend its strained relations with China to counter-flank Hanoi’s formidable military capabilities. But as expected from an offshore balancer, Indonesia ruled out direct military involvement, following an indirect strategy similar to the United Kingdom’s when confronting hegemonic threats.
As of 2025, Indonesia has, on paper, a massive power potential. It is home to 280 million people, not very far behind the United States. The several thousand-island-large archipelago has plenty of natural resources. Its large population and growing economy should allow it to play a leading role in Southeast Asia and the Indo-Pacific. Yet, without a hegemonic threat, little in Indonesia’s behaviour suggests a willingness to invest much in continental power politics. Its military spending is small compared to other leading powers, as it invests around one per cent of its GDP in defence.
But this is likely to change since Jakarta now faces a potential regional hegemon. China is well-positioned to reach hegemonic elevation over the Indo-Pacific and the Malay Archipelago. A Chinese hegemon would be strong enough to force unpleasant territorial and economic concessions on Indonesia and turn the country into a mere satellite.
Signs that Jakarta is taking action to counterbalance Beijing’s rise are unmistakable.
The country’s defence spending is increasing — under President Prabowo Subianto, it aims to spend one and a half per cent of its GDP on armed forces by 2029. There is now a strong willingness to overhaul the military in the face of the Chinese threat. Jakarta is especially interested in reinforcing the defences of its northernmost islands that are targeted by Beijing’s claims to rule the entire South China Sea.
A pivot towards the anti-hegemonic coalition accompanies this military awakening. Indonesia has increasingly shed its Cold War-era neutralist skin to move decisively towards the United States and its partners. Jakarta is eager to train with US troops, purchase US weapons and improve interoperability with US forces. Washington contributed to building a maritime training centre on Batam Island, which overlooks the Strait of Malacca. In June 2023, US B-52 strategic bombers made their first-ever visit to Indonesia — something inconceivable a decade earlier.
What comes next will depend on the regional balance of power. If it remains stable, Indonesia will face less incentive to confront China head-on. It will probably be content to rely on continental states and Washington for regional security.
But if Beijing keeps rising, Jakarta will feel hard-pressed to play the power politics game. The Chinese threat may force it to invest far more in defence and claim its mantle as a major power. Indonesia would also need to dedicate more energy to Southeast Asian security, notably by forming a closer alignment with Vietnam, Singapore, Malaysia, Thailand and the Philippines. Insularity offered security for decades, but this era is likely coming to an end.
Dylan Motin is Visiting Scholar at Seoul National University Asia Center and Non-resident Kelly Fellow at Pacific Forum.
