Arms control
Enactment: Arms control treaties and agreements are often seen as a way to avoid costly arms races which could prove counter-productive to national aims and future peace.  Some are used as ways to stop the spread of certain military technologies (such as nuclear weaponry or missile technology) in return for assurances to potential developers that they will not be victims of those technologies.  Additionally, some arms control agreements are entered to limit the damage done by warfare, especially to civilians and the environment, which is seen as bad for all participants regardless of who wins a war.
While arms control treaties are seen by many peace proponents as a key tool against war, by the participants, they are often seen simply as ways to limit the high costs of the development and building of weapons, and even reduce the costs associated with war itself.  Arms control can even be a way of maintaining the viability of military action by limiting those weapons that would make war so costly and destructive as to make it no longer a viable tool for national policy.

Enforcement: Enforcement of arms control agreements has proven difficult over time.  Most agreements rely on the continued desire of the participants to abide by the terms to remain effective.  Usually, when a nation no longer desires to abide by the terms, they usually will seek to either covertly circumvent the terms or to end their participation in the treaty.  This was seen with the Washington Naval Treaty (and the subsequent London Naval Treaty), where most participants sought to work around the limitations, some more legitimately than others.  The United States developed better technology to get better performance from their ships while still working within the weight limits, the United Kingdom exploited a loop-hole in the terms, the Italians misrepresented the weight of their vessels, and when up against the limits, Japan left the treaty. The nations which violated the terms of the treaty did not suffer great consequences for their actions.  Within little more than a decade, the treaty was abandoned. The Geneva Protocol  has lasted longer and been more successful at being respected, but still nations have violated it at will when they have felt the need.  Enforcement has been haphazard, with measures more a matter of politics than adherence to the terms.  This meant sanctions and other measures tended to be advocated against violators primarily by their natural political enemies, while violations have been ignored or given only token measures by their political allies.
More recent arms control treaties have included more stringent terms on enforcement of violations as well as verification.  This last has been a major obstacle to effective enforcement, as violators often attempt to covertly circumvent the terms of the agreements.  Verification is the process of determining whether or not a nation is complying with the terms of an agreement, and involves a combination of release of such information by participants  as well as some way to allow participants to examine each other to verify that information.  This often involves as much negotiation as the limits themselves, and in some cases questions of verification have led to the breakdown of treaty negotiations (for example, verification was cited as a major concern by opponents of the Comprehensive Test Ban Treaty, ultimately not ratified by the United States).
States may remain in a treaty while seeking to break the limits of that treaty as opposed to withdrawing from it. This is for two major reasons. To openly defy an agreement, even if one withdraws from it, often is seen in a bad light politically and can carry diplomatic repercussions. Additionally, if one remains in an agreement, competitors who are also participatory may be held to the limitations of the terms, while withdrawal releases your opponents to make the same developments you are making, limiting the advantage of that development.

Theory of arms control: Scholars and practitioners such as John D. Steinbruner, Thomas Schelling, Morton Halperin, Jonathan Dean or Stuart Croft worked extensively on the theoretical backing of arms control. Arms control is meant to break the security dilemma. It aims at mutual security between partners and overall stability (be it in a crisis situation, a grand strategy, or stability to put an end to an arms race). Other than stability, arms control comes with cost reduction and damage limitation. It is different from disarmament since the maintenance of stability might allow for mutually controlled armament and does not take a peace-without-weapons-stance. Nevertheless, arms control is a defensive strategy in principle, since transparency, equality, and stability do not fit into an offensive strategy.
According to a 2020 study in the American Political Science Review, arms control is rare because successful arms control agreements involve a difficult trade-off between transparency and security. For arms control agreements to be effective, there needs to be a way to thoroughly verify that a state is following the agreement, such as through intrusive inspections. However, states are often reluctant to submit to such inspections when they have reasons to fear that the inspectors will use the inspections to gather information about the capabilities of the state, which could be used in a future conflict.

History: 

Pre-19th century: One of the first recorded attempts in arms control was a set of rules laid down in ancient Greece by the Amphictyonic Leagues. Rulings specified how war could be waged, and breaches of this could be punished by fines or by war.
In the 8th and 9th centuries AD, swords and chain mail armor manufactured in the Frankish empire were highly sought after for their quality, and Charlemagne (r. 768–814), made their sale or export to foreigners illegal, punishable by forfeiture of property or even death.  This was an attempt to limit the possession and use of this equipment by the Franks' enemies, including the Moors, the Vikings and the Slavs.
The church used its position as a trans-national organization to limit the means of warfare. The 989 Peace of God (extended in 1033) ruling protected noncombatants, agrarian and economic facilities, and the property of the church from war. The 1027 Truce of God also tried to prevent violence between Christians. The Second Lateran Council in 1139 prohibited the use of crossbows against other Christians, although it did not prevent its use against non-Christians.
The development of firearms led to an increase in the devastation of war. The brutality of wars during this period led to efforts to formalize the rules of war, with humane treatment for prisoners of war or wounded, as well as rules to protect non-combatants and the pillaging of their property. However, during the period until the beginning of the 19th century few formal arms control agreements were recorded, except theoretical proposals and those imposed on defeated armies.
One treaty which was concluded was the Strasbourg Agreement of 1675. This is the first international agreement limiting the use of chemical weapons, in this case, poison bullets. The treaty was signed between France and The Holy Roman Empire

19th century: The 1817 Rush–Bagot Treaty between the United States and the United Kingdom was the first arms control treaty of what can be considered the modern industrial era, leading to the demilitarization of the Great Lakes and Lake Champlain region of North America.  This was followed by the 1871 Treaty of Washington which led to total demilitarization.
The industrial revolution led to the increasing mechanization of warfare, as well as rapid advances in the development of firearms; the increased potential of devastation (which was later seen in the battlefields of World War I) led to Tsar Nicholas II of Russia calling together the leaders of 26 nations for the First Hague Conference in 1899. The Conference led to the signing of the Hague Convention of 1899 that led to rules of declaring and conducting warfare as well as the use of modern weaponry, and also led to the setting up of the Permanent Court of Arbitration.

1900 to 1945: A Second Hague Conference was called in 1907 leading to additions and amendments to the original 1899 agreement.  A Third Hague Conference was called for 1915, but this was abandoned due to the First World War.
After the World War I, the League of Nations was set up which attempted to limit and reduce arms.  However the enforcement of this policy was not effective. Various naval conferences, such as the Washington Naval Conference, were held during the period between the First and Second World Wars to limit the number and size of major warships of the five great naval powers.
The 1925 Geneva Conference led to the banning of chemical weapons being deployed against enemy nationals in international armed conflict as part of the Geneva Protocol. The 1928 Kellogg-Briand Pact, whilst ineffective, attempted for "providing for the renunciation of war as an instrument of national policy".

Since 1945: After World War II, the United Nations was set up as a body to promote and to maintain international peace and security. The United States proposed the Baruch Plan in 1946 as a way to impose stringent international control over the nuclear fuel cycle and thereby avert a global nuclear arms race, but the Soviet Union rejected the proposal and negotiations failed. Following President Eisenhower's 1953 Atoms for Peace speech to the UN General Assembly, the International Atomic Energy Agency was set up in 1957 to promote peaceful uses of nuclear technology and apply safeguards against the diversion of nuclear material from peaceful uses to nuclear weapons.
Under the auspices of the United Nations, the Partial Test Ban Treaty, which aimed to end nuclear weapons testing in the atmosphere, underwater and in outer-space, was established in 1963. The 1968 Nuclear Non-Proliferation Treaty (NPT) was signed to prevent further spread of nuclear weapons technology to countries outside the five that already possessed them: the United States, the Soviet Union, the United Kingdom, France and China.