Editor's Note: (Marco Rubio is the Republican senator from Florida. He is a member of the Senate's Foreign Relations Committee, Intelligence Committee and Appropriations Committee. He also chairs the Congressional-Executive Commission on China that is authorized by US law to monitor human rights and the rule of law in the People's Republic of China. The views expressed in this commentary are his own.)
(CNN) America is reaffirming its commitment to securing a free and open Indo-Pacific region amid North Korea's nuclear and missile threats, China's increasingly assertive rise and other challenges. India and Japan, two of our key partners, have increased their security cooperation in response to regional challenges. But Washington must do more to support them and expand the involvement of Australia and other Asian democracies.
Much of the 21st century's history will be written in Asia. The region makes up nearly 60% of the world's population and roughly 40% of global GDP. Home to large and capable militaries, Asia accounts for the majority of the world's eight declared nuclear-armed nations, including North Korea.
Under President Xi Jinping, China is attempting to author its own version of the Indo-Pacific region's history. The People's Liberation Army is expanding and modernizing its military conventional and unconventional capabilities, including its vast arsenal of ballistic missiles and cruise missiles. It is also forcefully asserting Beijing's claims in territorial disputes with neighbors, including in the South China Sea and in the Doklam plateau at the Indo-Chinese border.
Furthermore, China is using its economic might to extend the long arm of its geopolitical influence, access and control, especially through its "Belt and Road Initiative" -- aggressively promoting infrastructure projects throughout Asia, Africa, the Middle East and Europe. It also recently established a naval base in Djibouti to enhance Chinese influence in the Indian Ocean and expeditionary capabilities.
To ensure the arc of history bends toward a free and open Indo-Pacific, regional democracies will have to cooperate more.
Under Prime Minister Narendra Modi, India's previous "Look East" approach has developed into a proactive "Act East" policy for deeper relations with other Asian countries. Modi, who has urged China to "reconsider its approach" to border and trade disputes, says "Act East" reflects India's desire to ensure maritime, space and cyber domains "remain avenues of shared prosperity, not become new theaters of contests."
Japan has emerged as a natural partner to India, given Tokyo's dependence on trade and energy flows through the Indian Ocean, its own territorial disputes with Beijing and its concerns about China's assertiveness. Indeed, Japanese Prime Minister Shinzo Abe declared that Tokyo and New Delhi "will strengthen our collaboration with those countries with whom we share universal values" during his September 2017 visit to India.
India and Japan have held military exercises for many years, most recently conducting a joint anti-submarine warfare exercise in the Arabian Sea last October. They have also issued joint statements to express concerns about unilateral provocations in the South China Sea, a reference to China's hostile activities.
Economic ties have deepened amid huge demand for infrastructure projects in India. Tokyo is India's third-largest source of foreign direct investment, and Abe recently touted a $17 billion bullet train project between Mumbai and Ahmedabad that Japan will finance with low-interest loans.
The United States should do more to support the Indo-Japanese partnership and expand multilateral cooperation. In a move widely seen as a response to China's "Belt and Road" initiative, the three countries agreed in September 2017 to cooperate on promoting infrastructure projects in Asia. It is critical for the US to work closely with India and Japan to implement these and other opportunities to cooperate with other nations that desire to counter Chinese influence.
The US should also facilitate and expedite more defense exports from the US and Japan, as well as Australia and South Korea. American military sales to India totaled more than $15 billion over the last decade, including sales of transport and maritime patrol aircraft, anti-ship missiles and helicopters, and should grow further after the US designated India a "major defense partner." Japan also has important amphibious aircraft and other defense platforms that India could use.
Stronger maritime cooperation among Asian democracies will be crucial. In 2015, Japan joined America and India as a permanent participant in the annual Malabar joint naval exercises. The US government should also encourage more trilateral exercises and explore incorporating Australia and other democracies into future exercises. It should also work to establish a network of stakeholders in the Indian Ocean, with the possible goal of creating a secretariat to promote freedom of navigation, stability, peace and trade in the region.
Expanding America's multilateral outreach with India and Japan to include Australia and other nations will take patience and sensitivity. But these four democracies -- including the US -- met for the first time in many years in Manila last month, and senior foreign ministry officials from India, Japan and Australia are set to meet this week in New Delhi. Given time, this quartet may yet find ways to engage more regularly and even expand.
To ensure the Indo-Pacific remains free and open, the US and regional democracies will have to increase communication. What's becoming clear is how much they can accomplish for the common good when they work together.