Is Vietnam a continental or a maritime power? And what domain should it prioritize to ensure its security in the age of rising Chinese power? This old debate has recently been revived by a series of scholarly exchanges since August, starting with my suggestion that Vietnam needs to pivot landward for its security given that the Paracel and the Spratly islands do not matter to its survival. Recently, Alexander Vuving joined the debate, arguing that a land-sea binary is no longer relevant to modern warfare, and that historically, Vietnam and its imperial predecessors had not ignored the sea during major land wars, as I suggested in my earlier writings. Vuving’s contribution is empirically important to the debate, for if Hanoi did not neglect the sea while fighting a land war against the United States and South Vietnam, my argument that Hanoi has always prioritized the land over the sea does not hold.
However, a close examination of history tells us otherwise. In addition to prioritizing continental threats, Vietnam has neither prioritized the sea nor won a naval battle that was fought far from its shore against a formidable enemy. The reason is simple. The offense-defense balance favors the defender on land and the offender at sea. On the open sea, there are no natural or man-made barriers or obstacles to conquests, and the navy cannot fall back onto friendly terrain or receive reliable supplies because there is no home base nearby to replenish food, fuel, spare parts, or ammunition. For instance, the Vietnam-occupied features in the Spratly Islands continue to rely on long-haul supplies from the mainland.
Even littoral warfare is distinct from open-ocean warfare due to the differences in the depth and breadth of water and the tidal ranges, which make littoral waters easier to defend than the open ocean. This explains why few states qualify as having a blue-water navy, while the shift from a littoral to a blue-water navy is often challenging. Naval warfare far from the coast thus benefits the side with more resources and better technology. To put it simply, the offense-defense balance increasingly favors the offender the farther the battle moves away from the landmass.
Vuving’s examples on Vietnam’s past use of naval power thus fall more into the category of littoral than blue-water warfare. Dai Viet successfully defeated the Chinese and the Mongol invaders from the sea not because it had a strong navy or prioritized the navy, but because those naval battles took place in littoral water, where the small Dai Viet ships could rely on the tide to decisively trap and destroy the bigger Chinese and Mongol ships using wooden stakes. And despite these littoral victories, Dai Viet’s land army and its “empty gardens, empty houses” strategy were vital to the final defeat of the northern invaders. The Dai Viet army could rely on the use of people’s warfare and friendly terrain to surround the stronger Chinese and Mongol armies while cutting off their supplies from the north. Had it not been for such friendly terrain, the smaller Dai Viet’s army could stand no chance against its enemies, for “empty gardens, empty houses” was a strategy of the weak. Dai Viet benefited from a defense-dominant domain.
Importantly, it is not about the means of military transport but the geographical location of the military objectives that matter in deciding whether Hanoi prioritized the land or the sea. During the Vietnam War, in addition to the Ho Chi Minh Trail, Hanoi transported supplies to the South via the sea. However, the number of supplies transported via the sea route was smaller than the land route. And from a broader perspective, Vietnam mostly fought against a land power and rarely a naval power. China, Mongolia, Champa, and South Vietnam were all land powers. For that reason, it seldom had to face the problem of a stretched logistics and an outdated navy often seen in blue-water warfare.
And while North Vietnam would capture South Vietnam-occupied Spratly islands in the closing stage of the Vietnam War, Hanoi’s successful captures do not mean it invested in the navy or it did not ignore the sea. Those captures better reflect the balance of power on land vis-à-vis Saigon than Hanoi’s naval capability. South Vietnam was already close to a total defeat when Hanoi launched the East Sea Campaign in April 1975. After unification, when facing a formidable enemy far from the shore, Vietnam lost a naval battle to China in 1988. Until today, despite efforts at military modernization, the Vietnamese navy is still no match for the Chinese navy in an open-sea battle. This demonstrates China’s resource and technological advantage in an offense-dominant domain.
Contrary to Vuving’s suggestion, the Hanoi leadership has clearly prioritized land objectives over maritime objectives. Former Prime Minister Pham Van Dong was perceived to have tacitly endorsed the Chinese declaration of sovereignty over the territorial water and the Paracel and Spratly islands in 1958, which now forms the basis of the Chinese position on the maritime disputes vis-à-vis Vietnam. Hanoi downplayed the significance of those islands while it was preoccupied with fighting South Vietnam and to maintain good relations with the Chinese ally. Hanoi only seriously pressed its claims against China’s after it solved the most pressing land security threat in 1975.
This is not to question whether North Vietnamese leaders made a normatively correct choice, but under such a circumstance of scarcity, strategic orientation towards the more dangerous threat was simply logical. Had Hanoi really considered the South China Sea vital to its survival, it would not have neglected the islands during the War or waited until April 1975 to capture islands occupied by South Vietnam. Using maritime routes to transport supplies against a continental threat is not evidence that Hanoi prioritized the sea.
Vuving is correct to point out that China currently poses the greatest threat to Vietnam. However, his suggestion that we avoid thinking with the land-sea binary ignores Vietnam’s long-term strategic orientation toward the land when there is a land security threat. As mentioned above, the nature of open-sea warfare is fundamentally different from that of continental warfare, and states always face an opportunity cost when deciding between developing the army or the navy. Weapons vital to capturing or holding a piece of territory such as tanks cannot be used to assert maritime sovereignty in the open sea. Destroyers are never fit to stand against an invading land army.
To be clear, the risk of a Chinese land invasion of Vietnam is small; however, if such an invasion were to happen, the consequences would be detrimental to Vietnam. On the other hand, while the risk of a Chinese naval attack is relatively higher, losing several islands does not hurt Vietnam’s survival or fundamentally alter the balance of power on land between Vietnam and China. This is not to suggest that Hanoi should abandon its islands, but when there is a clear land threat, it should be ready to allocate its resources wisely, as it did during the Indochina wars. We do not know where China’s “second lesson” will take place, but we know where Vietnam should prioritize in order to ensure its best chance of survival.
Whether Vietnam recognizes it or not, it has always had a grand strategy. And such a grand strategy reflects the country’s geographical vulnerabilities and its general lack of agency. As a land power bordering a body of water, Vietnam has many times prioritized addressing land threats before looking eastward. Even the Vietnamese term for “country” (dat nuoc) suggests so: it is no surprise that the word “land” (dat) comes before “water” (nuoc).