Power vacuum in the context of "Christian I of Denmark"

An interregnum (plural interregna or interregnums) is a period of discontinuity or "gap" in a government, organization, or social order. Archetypally, it was the period of time between the reign of one monarch and the next (coming from Latin inter-, "between" and rēgnum, "reign" [from rex, rēgis, "king"]), and the concepts of interregnum and regency therefore overlap. Historically, longer and heavier interregna have been typically accompanied by widespread unrest, civil and succession wars between warlords, and power vacuums filled by foreign invasions or the emergence of a new power.

The term also refers to the periods between the election of a new parliament and the establishment of a new government from that parliament in parliamentary democracies, usually ones that employ some form of proportional representation that allows small parties to elect significant numbers, requiring time for negotiations to form a government. In the UK, Canada and other electoral systems with single-member districts, this period is usually very brief, except in the rare occurrence of a hung parliament as occurred both in the UK in 2017 and in Australia in 2010. In parliamentary interregnums, the previous government usually stands as a caretaker government until the new government is established. Additionally, the term has been applied to the United States presidential transition, the period of time between the election of a new U.S. president and their inauguration, during which the outgoing president remains in power, but as a lame duck.

In February and March 2014, Russia invaded the Crimean Peninsula, part of Ukraine, and then annexed it. This took place in the relative power vacuum immediately following the Revolution of Dignity. It marked the beginning of the Russo-Ukrainian War.

The events in Kyiv that ousted Ukrainian president Viktor Yanukovych on 22 February 2014 sparked both pro-Russian and anti-separatism demonstrations in Crimea. At the same time, Russian president Vladimir Putin told his security chiefs to begin work on "returning Crimea to Russia". On 27 February, Russian special forces without insignia seized strategic sites across Crimea. Russia at first denied involvement, but Putin later admitted that they were Russian troops. As the armed men occupied Crimea's parliament, it dismissed the Crimean government, installed the pro-Russian Aksyonov government, and announced a referendum on Crimea's status. The referendum was held under Russian occupation and, according to the Russian-installed authorities, the result was overwhelmingly in favor of joining Russia. The next day, 17 March 2014, Crimea's authorities declared independence and requested to join Russia. Russia formally incorporated Crimea on 18 March 2014 as the Republic of Crimea and federal city of Sevastopol. Following the annexation, Russia militarized the peninsula and warned against any outside intervention.

The Warlord Era was the period in the history of the Republic of China between 1916 and 1928, when control of the country was divided between rival military cliques of the Beiyang Army and other regional factions. It began after the death of Yuan Shikai, the President of China after the Xinhai Revolution had overthrown the Qing dynasty and established the Republic of China in 1912. Yuan's death on 6 June 1916 created a power vacuum which was filled by military strongmen and widespread violence, chaos, and oppression. The Nationalist Kuomintang (KMT) government of Sun Yat-sen, based in Guangzhou, began to contest Yuan's Beiyang government based in Beijing for recognition as the legitimate government of China.

The most powerful cliques were the Zhili clique led by Feng Guozhang, who controlled several northern provinces; the Anhui clique led by Duan Qirui, based in several southeastern provinces; and the Fengtian clique led by Zhang Zuolin, based in Manchuria. The three cliques often engaged in conflict for territory and hegemony. In mid-1917, after Yuan's successor Li Yuanhong attempted to remove Duan as premier, the general Zhang Xun forced Li to resign and made a brief attempt to restore the Qing dynasty, which was quashed by Duan's troops. Feng became the acting president, but was forced to step down by Duan in late 1918 and was replaced by Xu Shichang. In mid-1920, the new Zhili clique leaders, Cao Kun and Wu Peifu, defeated Duan in the Zhili–Anhui War in an alliance with Zhang Zuolin. A power struggle broke out between Cao and Zhang which ended with Cao's victory in the First Zhili–Fengtian War in 1922. Cao was president until 1924, when during the Second Zhili–Fengtian War he was betrayed by his subordinate Feng Yuxiang, who joined with Zhang to stage a coup against Cao. Feng and Zhang shared power and recalled Duan to serve as president before Zhang removed them both in 1926; in 1927, he declared himself Generalissimo.

The Somali Civil War (Somali: Dagaalkii Sokeeye ee Soomaaliya; Arabic: الحرب الأهلية الصومالية al-ḥarb al-’ahliyya aṣ-ṣūmāliyya) is an ongoing civil war that is taking place in Somalia. It grew out of resistance to the military junta which was led by Siad Barre during the 1980s. From 1988 to 1990, the Somali Armed Forces began engaging in combat against various armed rebel groups, including the Somali Salvation Democratic Front in the northeast, the Somali National Movement in the Somaliland War of Independence in the northwest, and the United Somali Congress in the south. The clan-based armed opposition groups overthrew the Barre government in 1991.

Various armed factions began competing for influence in the power vacuum and turmoil that followed, particularly in the south. In 1990–92, customary law temporarily collapsed, and factional fighting proliferated. In the absence of a central government, Somalia became a "failed state". This precipitated the arrival of UNOSOM I UN military observers in July 1992, followed by the larger UNITAF and UNOSOM II missions. Following an armed conflict between Somali insurgents and UNOSOM II troops during 1993, the UN withdrew from Somalia in 1995. After the central government's collapse and the withdrawal of UN forces, there was some return to customary and religious law in most regions. In 1991 and 1998, two autonomous regional governments were also established in the northern part of the country: Somaliland and Puntland. In the south Islamic Sharia courts began proliferating in response to lawlessness. This led to a relative decrease in the intensity of the fighting, with the Stockholm International Peace Research Institute removing Somalia from its list of major armed conflicts for 1997 and 1998.

In February and March 2014, Russia invaded the Crimean Peninsula, part of Ukraine, and then annexed it. This took place in the relative power vacuum immediately following the Revolution of Dignity. It marked the beginning of the Russo-Ukrainian war.

The events in Kyiv that ousted Ukrainian president Viktor Yanukovych on 22 February 2014 sparked both pro-Russian and anti-separatism demonstrations in Crimea. At the same time, Russian president Vladimir Putin told his security chiefs to begin work on "returning Crimea to Russia". On 27 February, Russian special forces without insignia seized strategic sites across Crimea. Russia at first denied involvement, but Putin later admitted that they were Russian troops. As the armed men occupied Crimea's parliament, it dismissed the Crimean government, installed the pro-Russian Aksyonov government, and announced a referendum on Crimea's status. The referendum was held under Russian occupation and, according to the Russian-installed authorities, the result was overwhelmingly in favor of joining Russia. The next day, 17 March 2014, Crimea's authorities declared independence and requested to join Russia. Russia formally incorporated Crimea on 18 March 2014 as the Republic of Crimea and federal city of Sevastopol. Following the annexation, Russia militarized the peninsula and warned against any outside intervention.

Following the fall of the Assad regime on 8 December 2024, Israel invaded the buffer zone in southwestern Syria (adjacent to the Israeli-occupied Golan Heights) and has continued to occupy it. Israel also carried out an aerial bombing campaign to cripple the new Syrian Armed Forces, and demanded that it stay out of southern Syria. Israel's government claimed this was to thwart any "potential threat" from post-war Syria.

Israel took advantage of the power vacuum created by the fall of former Syrian president Bashar al-Assad to increase the amount of territory it controlled by several hundred square miles. Israel declared the 1974 Agreement on Disengagement with Ba'athist Syria to be void. Israel initially said this new invasion would be "temporary", but later said it would hold onto the territory for an "unlimited time". Israel also launched extensive aerial and naval strikes on Syrian military targets across the country, under an operation codenamed Operation Arrow of Bashan (Hebrew: מבצע חץ הבשן, romanized: Mivtza Ḥetz HaBashan). Israel's campaign crippled Syria's military capabilities, including its army and its navy, and destroyed its chemical weapons stockpiles.

The Siamese–Vietnamese wars were a series of armed conflicts between the Siamese Ayutthaya Kingdom and Rattanakosin Kingdom and the various dynasties of Vietnam mainly during the 18th and 19th centuries. Several of the wars took place in modern-day Cambodia.

The political, dynastic, and military decline of the Khmer Empire after the 15th century, known as the Post-Angkor Period, left a power vacuum in the Mekong floodplains of central Indochina. United under strong dynastic rule, both Siam to the west and Vietnam to the east sought to achieve hegemony in the lowland region and the Lao mountains. The Siamese introduced — and Vietnam soon followed — the hostage system for Cambodian royals, who were relocated to their courts, actively undermining royal affairs and shaping future Cambodian policies. Eventually, territory was annexed by both powers, who conceived, maintained and supported their favorable Cambodian puppet kings. Actual combat mainly took place on Cambodian territory or on occupied lands. The 19th-century establishment of French Indochina put an end to Vietnamese sovereignty and to Siamese policies of regional expansion. Subsequent clashes of the two countries were not caused by regional rivalry, but must be viewed in the context of the 20th-century imperial policies of foreign great powers and the Cold War.