The U.S. war against Iran is teaching Vietnam two important lessons in real time. First, it shows Vietnam the limits of U.S. military power. Iran, despite being surrounded by U.S. allies and possessing an inferior navy and air force, has still been able to close the Strait of Hormuz and survive politically in the face of massive U.S. bombardments. The United States has little chance of victory were it to attempt to challenge China’s much more sophisticated arsenal.

Second, it demonstrates to Hanoi how fragile the liberal international order is now that the United States has decided to undermine its principles of sovereignty, territorial integrity, and open trade. Washington’s “enshitification” of the international order to extort allies and partners for money and influence raises Hanoi’s skepticism of U.S. sincerity as a trade and security partner.

The U.S. conduct confirms the validity of Hanoi’s “Four Nos” policy of no military alliances, no siding with one country against another, no foreign military bases, and no use of Vietnamese territory to oppose other countries, no use of force or threats to use force in international relations. (The fourth “no” was added in 2019). The U.S. use of its Middle East bases to bomb Iran has invited Iranian retaliation against critical infrastructure in Saudi Arabia, Qatar, Kuwait, Jordan, and the United Arab Emirates, and disturbed these countries’ delicate balance between Washington and Tehran. Even faraway allies such as Japan, South Korea, and Australia have been criticized for not helping reopen the Strait of Hormuz. By neither allying with the United States nor granting its access to bases, Vietnam simultaneously ensures that it will not be the target of Chinese retaliation and entrapped in U.S. operations elsewhere.

Washington’s rogue use of force now requires Hanoi to be even more proactive with its Four Nos. Vietnam’s economic development needs a predictable and open international order. The Four Nos should no longer be viewed just as a policy of self-restraint but also as a measure to restrain Hanoi’s neighbors and prevent them from coalescing into rival military blocs due to the U.S. disregard for the international order. This requires an expansion of the Four Nos beyond Vietnam’s territory. Vietnam’s goal should be straightforward: requiring all its neighbors and diplomatic partners to adhere to the Four Nos in their bilateral exchanges.

Vietnam came up with its “Three Nos” in response to the collapse of the Soviet-led order in 1991. During the Third Indochina War (1978-1991), Hanoi granted the Soviet Union access to Cam Ranh Naval Base, which Moscow could use to monitor China and Southeast Asia. At the same time, Vietnam’s military presence in Laos and Cambodia denied China the ability to attack Vietnam from the west. However, Vietnam’s neighbors saw its conduct and its alliance with the Soviet Union as a threat, which led them to use military, economic, and diplomatic pressure to force Hanoi to stop the use of others’ territories or let others use Vietnamese territory for military purposes.

Due to declining Soviet backing after 1986, Hanoi had to withdraw troops from Laos and Cambodia in 1988 and 1989, respectively. At the same time, the Soviet Union also withdrew its fighters and bombers from Vietnam and reduced its presence at Cam Ranh. Since its formal adoption in 1998, Vietnam has treated the Three Nos, and later the Four Nos, as the core of its defense policy and an affirmation of its pledge under the 1991 Paris Agreement not to send troops to Cambodia again. After Russia’s lease of the naval base expired in 2004, Hanoi has refused to let foreign navies station permanently there. Restraining its use of force and foreign military presence on its soil has allowed Hanoi to successfully normalize ties with China and the ASEAN countries and helped the economy to grow at an annual rate of 6.7 percent between 1990 and 2024.

The Four Nos is the bedrock of Vietnam’s economic rise and its integration into a non-Soviet order for two reasons. First, it made Vietnam’s conduct predictable and open to its neighbors. Military flashpoints in its vicinity did not make Hanoi change course. Vietnam has eschewed the use of force in resolving the maritime disputes with China and its ASEAN neighbors, and, unlike during the Third Indochina War, it rejected the notion of sending troops to participate in the recent Thailand-Cambodia border conflict. The sea lanes in the South China Sea remain open despite Vietnam’s disputes with China and other nations. Predictability dampens the risk of a regional arms race. Openness fosters prosperity and raises the costs of war.

Second, the Four Nos help Vietnam avoid being dragged into a great-power competition along the line of the Sino-Soviet Split. By restricting its own choice of allies, Vietnam ensures that its great power partners do not have to worry about winning Vietnam’s allegiance by all means necessary to deny other powers access to Vietnam’s bases and resources. Vietnam’s rejection of alliances resolves the alliance security dilemma. Its participation in a particular international grouping, such as U.S. President Donald Trump’s Board of Peace, does not mean that Hanoi is siding with one great power against another. On the contrary, joining many groupings strengthens Vietnam’s non-alignment.

As the United States is in relative decline vis-à-vis China, it may seek bases in Southeast Asia or unilaterally use force to contest China’s growing grip on the First Island Chain. Vietnam’s Four Nos can be applied to manage Washington’s rogue use of force and the decline of the U.S.-led order. In addition to unilaterally restricting its own conduct, Vietnam must strive to restrict that of others via bilateral exchanges to ensure the regional order remains predictable and open. This means that Vietnam should get its partners to commit to rejecting the use of or threat of force in the Indo-Pacific and not to host foreign militaries on their soil. Vietnam’s successful expansion of its Four Nos to its partners would convince the great powers not to pressure Southeast Asian countries to host military bases or to “pick a side” in their strategic rivalries. No country would use force or threaten to use force to close the Strait of Malacca and the South China Sea. Rejecting great-power intervention in regional affairs, such as during the Thailand-Cambodia border skirmishes, is a must for maintaining the regional order.

A bilateral commitment to Four Nos from its regional partners will benefit Vietnam as well. Vietnam’s military presence in Laos and Cambodia was intended to prevent these countries from being exploited as staging areas for attacks against Vietnam. Vietnam can achieve the same objective at a lower cost if its diplomatic partners promise not to use their own or other countries’ territories against Vietnam. At the same time, Vietnam’s neighbors not hosting foreign bases will discourage them from betting on external support to escalate existing disputes and prevent them from being military targets in the event of a conflict.

Besides the perceived U.S. threat to Vietnam’s political system, its rogue use of force now looms as an equally threatening development. Hanoi not only wants Washington to respect its communist government but also the order that it needs to thrive economically. An expanded understanding of Four Nos will complement Vietnam’s “era of national rise.” Vietnam’s Four Nos has kept the country out of a great-power competition for more than three decades; it can help keep the region out too.