Defense pact in the context of "Socii"

Collective security is arrangement between states in which the institution accepts that an attack on one state is the concern of all and merits a collective response to threats by all. Collective security was a key principle underpinning the League of Nations and the United Nations. Collective security is more ambitious than systems of alliance security or collective defense in that it seeks to encompass the totality of states within a region or indeed globally.

The premise of a collective security arrangement is that it serves as a deterrent to aggression by committing an international coalition against any aggressor. While collective security is an idea with a long history, its implementation in practice has proved problematic.

A military alliance is a formal agreement between nations that specifies mutual obligations regarding national security. In the event a nation is attacked, members of the alliance are often obligated to come to their defense regardless if attacked directly. Military alliances can be classified into defense pacts, non-aggression pacts, and ententes. Alliances may be covert (as was common from 1870 to 1916) or public.

According to a 2002 dataset of military alliances, there have been 538 alliance treaties from 1815 to 2003. The vast majority of the alliances involve commitments to come to the military support of one ally involved in war. The vast majority are defensive in nature. Since the end of the Second World War, military alliances have usually behaved less aggressively and act more as a deterrent. A 2025 analysis of alliances across the 19th and 20th century found that alliances overall tend to deter war.

The Treaty of Defensive Alliance was a secret defense pact between Bolivia and Peru. Signed in the Peruvian capital, Lima, on 6 February 1873, the document was composed of eleven central articles that outlined its necessity and stipulations and one additional article that ordered the treaty to be kept secret until both contracting parties decided otherwise. The signatory states were represented by the Peruvian Foreign Minister José de la Riva-Agüero y Looz Corswaren and the Bolivian Envoy Extraordinary and Minister Plenipotentiary in Peru, Juan de la Cruz Benavente.

Ongoing border disputes between Bolivia and Chile worsened South America's tense political environment, which was made all the more precarious by a global economic depression. The system of mutual defense established between Bolivia and Peru sought to protect their national security and the regional balance of power by containing Chilean expansionism, which was fueled by Chile's economic ambitions over the mineral resources of the Atacama Desert. The pact's stated intentions were to guarantee the integrity, independence, and sovereignty of the contracting parties.

An entente (/ɑːnˈtɑːnt/) is a type of treaty or military alliance in which the signatories promise to consult each other or to cooperate in the event of a crisis or military action. Examples include the Entente Cordiale between France and the United Kingdom and the Triple Entente between France, Russia and the United Kingdom.

It has been found that during wars, signatories of ententes are less likely to assist each other than signatories of defense pacts but more likely than signatories of non-aggression pacts. It has also been found that great powers are less likely to start wars against their partners in ententes than against their partners in nonaggression and defensive pacts or states with no alliance with them.

The Mutual Defense Treaty between the United States and the Republic of China (formally known as Mutual Defense Treaty between the United States of America and the Republic of China), was a defense pact signed between the United States and the Republic of China (Taiwan) effective from 1955 to 1980. It was intended to defend the island of Taiwan from invasion by the People's Republic of China. Some of its content was carried over to the Taiwan Relations Act of 1979 after the failure of the Goldwater v. Carter lawsuit.

The Treaty of Värälä (sometimes known as the Treaty of Wereloe) was signed in Värälä, Elimäki Municipality, Finland, between Russia (represented by Otto Heinrich Igelström) and Sweden (represented by Gustaf Mauritz Armfelt). It was signed on 14 August 1790 and concluded the Russo-Swedish War. The treaty confirmed status quo ante bellum with respect to the borders; however, Russia's right to interfere with Swedish interior affairs from the Treaty of Nystad was expressly revoked. The provisions of the previous Treaty of Åbo were basically confirmed.

A year later, on 19 October 1791, a convention was signed in Stockholm, whereby the countries pledged to assist each other in case of foreign attack. The treaty anticipated the First Coalition in its being directed against Revolutionary France. Catherine bound herself to pay her new ally annual subsidies amounting to 300,000 rubles. Gustav III had sent to his cousin, Catherine II of Russia, a letter in which he besought her to "forget the war as a passing cloud" and invoked their common blood as his claim to enjoy amitie with his cousin.