President Joe Biden and the prime ministers of Australia and the United Kingdom announced a new defense partnership in September, surprising both allies and competitors.

The AUKUS initiative enraged France, which lost out on the sale of submarines worth nearly $60 billion, and alarmed China, which sees the pact as a direct threat.

Although AUKUS leaders claim that their initiative is not targeted at any specific country, it is clear that the agreement was designed to counter Chinese influence and ambitions in the Indo-Pacific region.

The pact is centered on an agreement for the United States and the United Kingdom to provide nuclear-propulsion technology to Australia, but this is only the tip of the iceberg in terms of collaboration between the three countries. Their collaboration dates back decades, with special-operations forces playing an important role.

Most modern Western special-operations units can be traced back to the British Special Air Service during WWII. During the last two decades of war in the Middle East and Africa, the commonalities that resulted became clear.

Allied nations frequently train together to ensure interoperability, learn from one another, and hone their warfighting skills in a more realistic environment. The US Army’s Delta Force has a close relationship with the Australian SAS, and the two units frequently train together in both countries.

In addition to regular training, the three countries’ special-operations communities maintain close ties through exchange programs in which individuals or groups from one unit spend time serving with one of their direct counterparts. These exchange programs have been around for a long time.

The majority of exchanges occur at the Tier 1 level, between the United States’ Delta Force and Naval Special Warfare Development Group (formerly known as SEAL Team 6), Australia’s Special Air Service Regiment (SASR), and the United Kingdom’s Special Air Service (SAS) and Special Boat Service (SBS). Other Tier 1 units from the United States and the United Kingdom, according to insiders, also exchange operators, though the specific units and their activities have not been publicly disclosed.

Australian commandos have participated in exchange programs with Delta Force and the Naval Special Warfare Development Group in the United States. Similarly, American special forces personnel have been assigned to the Australian SAS. During the Vietnam War, Australian SAS troopers joined Navy SEAL platoons in the Mekong Delta to hunt down Vietcong insurgents.

Special-operations units in the United States have a close relationship with their counterparts in the United Kingdom. Delta Force, the US Army’s premier counterterrorism and hostage-rescue unit, was founded after its founder, Col. Charlie Beckwith, a young Green Beret at the time, spent two years as an exchange officer with the SAS.

Two of the eight troopers deployed with the British SAS unit involved in the infamous Bravo Two Zero mission during the first Gulf War were not British. One was an ex-Australian Commando, and the other was a New Zealander on exchange from the New Zealand Special Air Service.

Their actions on the ground are sometimes recognized, and their names or unit affiliations are revealed. The same is true for exchange programs. During the early days of the Afghan war, an exchange program between the Naval Special Warfare Development Group and the British Special Boat Service drew unexpected attention.

In the weeks following the September 11 attacks, US and coalition special-operations forces joined anti-Taliban fighters in an attempt to depose the Taliban and Al Qaeda. Hundreds of Taliban prisoners held in a fortress in Mazar-e-Sharif revolted, killing CIA officer Mike Spann, the first American to die in Afghanistan, while Delta Force was searching for Osama bin Laden in the Tora Bora mountains. Green Berets, CIA officers, and an SBS team joined anti-Taliban fighters and quickly put an end to the insurgency.

One SBS member’s actions revealed the scope of these exchange programs. Chief Petty Officer Stephen Bass was awarded the Navy Cross, the United States’ second-highest valor award, as well as the British Military Cross. Although Bass’ parent unit was listed as SEAL Team 1, he was actually a SEAL Team 6 operator on a two-year exchange program with the British.

While the AUKUS pact focuses on defense technology, it also provides an opportunity for the special-operations communities of the three countries to collaborate even more closely in order to counter Chinese influence and aggression in the Indo-Pacific.