The Five Most Important Arms-Control Agreements

TNI takes a look at the five most important arms-control agreements of the 20th and 21st centuries, with a focus on how they changed the behavior of governments and the conduct of war.

We’ve been taught to expect that nations will seek to defend themselves through every measure available to them. International law has rarely offered significant protection to the weak, and multilateral efforts at controlling how states develop, spread and amass weapons have regularly been met with scorn and derision.

But sometimes states come together, and for one reason or another agree to give up their rights to unilaterally build up arms. Many arms-control arrangements have failed; some have succeeded, and in many cases the story is mixed. This article takes a look at the five most important arms-control agreements of the 20th and 21st centuries, with a focus on how they changed the behavior of governments and the conduct of war.

Washington Naval Treaty

Just after World War I, Japan, the United States and the United Kingdom embarked on ambitious programs of naval construction designed to provide supremacy over any would-be foe. There was no doubt, however, that the expense of a new arms race would prove beyond the means of several of the competitors. In the wake of the war, the United Kingdom simply lacked the resources to match U.S. construction. Japan was willing to make a game of it, but the ambitious construction program of the IJN would have overwhelmed the Japanese economy. New battleships proved a tough sell to the U.S. Congress.

The Washington Naval Treaty of 1922, negotiated between the five major naval powers (the United Kingdom, the United States, Japan, Italy and France) set specific quotas for battleship ownership (18:18:10:6:6). It also limited battleship size to 35,000 tons, and battleship guns to 16”. The treaty determined that any ship larger than 10,000 tons, or carrying guns heavier than 8”, would be deemed a battleship. Navies around the world, although mostly the USN and the Royal Navy, scrapped acres of aging battleships.

The follow-up London Naval Treaty of 1930 set limits on the size of the auxiliary fleet and mandated the scrapping of additional battleships (15:15:9). A Second London Naval Treaty, taking force in 1936, essentially gave up on the project of arms limitation because of the defection of Japan.

The treaty didn’t prevent World War II, and the decision of the Japanese and Italians to defect in the 1930s certainly gave them a leg up on the next war. However, the Washington Naval Treaty surely slowed battleship construction and the increase of battleship size, and prevented several governments from impoverishing themselves in the 1920s to no good effect.

Geneva Protocol

The first major lethal gas attack of World War I took place in April 1915, when German forces unleashed a barrage of chemical shells on French colonial positions at the Second Battle of Ypres. The gas attack opened a major hole in the French lines, but the Germans failed to exploit it.

Further uses of chemical weapons on the Western Front made a horrible war even more horrific. Soldiers could defend themselves from chemical attacks through the use of protective clothing and gas masks. In practice, these measures made life in the trenches even more uncomfortable for the soldiers.

The use of poison gas deeply colored memory of the war, such that the great powers undertook multilateral efforts to limit the use of such munitions in the future. In the 1920s, optimism ran high about the prospect of banning various kinds of warfare, including chemical weapons, strategic bombing and unrestricted submarine campaigns. Efforts on the latter two succumbed to international bickering, institutional interest and military necessity. The Geneva Protocol on chemical weapons, signed in 1925, stuck.

The Protocol didn’t entirely prevent chemical-weapons usage during the ensuing sixty-five years (until the conclusion of the Chemical Weapons Convention). The Italians used gas in Ethiopia, the Japanese in China, and the Iraqis and Iranians against one another in the Persian Gulf War. Still, the apparent break from practice in World War I is remarkable; World War II saw almost no chemical-weapon use between major combatants.

The Protocol doesn’t deserve all the credit. Chemical weapons are tough (although not impossible) to manage in combat. The major combatants worried about reprisal attacks (although this didn’t prevent the resort to strategic bombing or unrestricted submarine warfare). Poison gas had acquired a horrific reputation even before the Protocol (as had other forms of warfare). Finally, the treaty left a variety of loopholes that states could have exploited if they saw fit.

Still, it’s hard to plausibly conclude that the treaty had no effect on military decision making. Many expected that World War II and the various brushfire conflicts of the Cold War would descend into chemical conflagration, but it never happened. In large part this was because of the fear, disgust and revulsion caused by the use of gas, the memory of which depended, to great extent, on the successful use of international means to make such attacks illegal.

Nuclear Non-Proliferation Treaty