The QUAD is an informal strategic alliance between the US, Japan, Australia, and India that was first proposed in 2007 but originated following joint relief efforts after the 2004 Indian Ocean tsunami. While intended as an indirect counter to China's growing power, China issued protests that caused Australia to withdraw briefly. The QUAD was reinstated in 2017 and currently aims to uphold international maritime law and facilitate economic cooperation, especially regarding vaccine production, though China has warned nations not to join what it views as an anti-China alliance.