The Israel Defense Forces (IDF) was officially established on May 31, 1948, shortly after the founding of the State of Israel. The IDF incorporated pre-state Jewish paramilitary organizations, including the Haganah, Palmach, Irgun and Lehi.
Immediately after it gained independence, Israel was invaded by the armies of Egypt, Jordan, Syria, Lebanon and Iraq, sparking the War of Independence (May 1948-July 1949). Through effective organization, the IDF was able to overcome the manpower and supply advantages held by its Arab enemies. The final armistice agreement was signed in July 1949, ending the War of Independence.
In the early years of statehood, Israel was beset by security problems, as its Arab neighbors frequently violated the 1949 armistice agreements. Israeli and Israel-bound ships were prevented from traversing the Suez Canal; the Straits of Tiran were blockaded; terrorists constantly infiltrated into Israel from neighboring Arab countries to carry out attacks; and the Egyptian military increased its presence in the Sinai Peninsula.
In October 1956, Egypt, Jordan and Syria signed a tripartite military alliance, increasing the imminent military threat facing Israel. On October 29, 1956, Israel launched an eight-day campaign (the Sinai Campaign) during which the IDF took control of the Gaza Strip and the Sinai Peninsula. Following international pressure, Israel withdrew from these territories in stages. The withdrawal was complete in March 1957. United Nations forces were positioned along the Israel-Egypt border and Israeli ships were assured the right of passage through the Straits of Tiran.
The following decade was relatively quiet, allowing Israel and the IDF to develop.
In May 1967, Egypt increased its military presence in the Sinai Peninsula, expelled the UN forces on the Israel-Egypt border, closed the Straits of Tiran to Israeli shipping and signed a defense pact with Jordan. Facing an existential threat, Israel invoked its right to self-defense. On the morning of June 5, the IDF launched a pre-emptive strike against Egypt, starting the Six-Day War. Jordan launched attacks on Israel, drawing a response from the IDF. Conflict also broke out with Syria in the north. Over the course of six days, the IDF took control of the Sinai Peninsula and the Gaza Strip from Egypt, the West Bank (including East Jerusalem) from Jordan and the Golan Heights from Syria.
Following the Six-Day War, Israel hoped that it could convert its military success into permanent peace with its Arab neighbors, based on UN Security Council Resolution 242. Israel's diplomatic overtures, however, were rebuffed.
Shortly after the conclusion of the Six-Day War, Egypt initiated the War of Attrition against Israel, with sporadic actions along the Suez Canal that escalated into intense, localized clashes that caused many casualties on both sides between 1967 and 1970. In 1970, a renewed cease-fire was reached between Israel and Egypt.
On October 6, 1973, which was Yom Kippur (the holiest day of the Jewish year), Egypt and Syria launched a coordinated surprise attack against Israel, with Egyptian forces crossing the Suez Canal and Syrian forces entering the Golan Heights. Over three weeks of heavy battles, the IDF overcame initial Egyptian and Syrian gains and advanced to the western side of the Suez Canal and to the vicinity of the Syrian capital of Damascus. Negotiations in the following years led to disengagement agreements under the terms of which Israel withdrew from parts of the territories captured by the IDF during the Yom Kippur War.
In 1979, Israel and Egypt signed a peace agreement. Under the terms of the agreement, Israel fully withdrew from the Sinai Peninsula.
Repeated attacks on Israel's northern towns by the Palestinian Liberation Organization (PLO), which was based in southern Lebanon after being expelled from Jordan in 1970, led to the outbreak of Operation Peace for Galilee in 1982. The IDF entered southern Lebanon and removed the bulk of the PLO's infrastructure in the area. Until May 2000, the IDF remained in a narrow security zone in southern Lebanon to protect northern Israel against attacks by hostile elements in Lebanon.
In December 1987, the First Intifada (uprising) broke out in the West Bank, East Jerusalem and the Gaza Strip. It was initiated by Palestinians in the Jabalia refugee camp in Gaza. Over the course of the First Intifada, Palestinians carried out thousands of attacks against Israeli civilians and soldiers using weapons such as Molotov cocktails, hand grenades, guns and explosives.
In 1993, Israel and the PLO signed the Oslo Accords, leading to years of peace negotiations. Parts of the West Bank, including its population centers, were handed over by Israel to the Palestinian Authority. Despite these peace process, the Hamas and Islamic Jihad terrorist organizations carried out numerous attacks inside Israel during the 1990s, including the first suicide bombings carried out by carried out by Palestinians.
Israel and Jordan signed a peace agreement in 1994.
In September 2000, Palestinians launched the Second Intifada (uprising). Hundreds of Israeli civilians and soldiers were killed in Palestinian terrorist attacks that included numerous suicide bombings and shooting attacks in Israeli cities.
In March 2002, following a Hamas suicide bombing at a Passover seder at a Netanya hotel in which 30 people were killed, the IDF carried out Operation Defensive Shield to eliminate Palestinian terrorist infrastructure in the West Bank. Operations conducted by IDF in Palestinian cities in the West Bank led to a decrease in Palestinian terrorist attacks inside Israel. The construction of a security barrier between Israel and the West Bank also contributed to the decline in Palestinian terrorism.
In 2004, Israel decided to disengage from the Gaza Strip. All Israeli citizens and military personnel in Gaza were evacuated in August 2005.
On July 12, 2006, Hezbollah terrorists launched an attack on IDF soldiers patrolling the Israel-Lebanon border within Israeli territory. The attack instigated the Second Lebanon War. The war lasted 34 days and ended with the adoption of UN Resolution 1701. During the war, the IDF significantly degraded Hezbollah's military capabilities through airstrikes and ground operations in Lebanon.
Following years of rocket fire aimed at southern Israeli towns by terrorists in the Gaza Strip, the IDF launched Operation Cast Lead on December 27, 2008. During the three-week operation, IDF forces carried out operations against Hamas and other terrorist organizations in the Gaza Strip. After the operation, the frequency of rocket fire from the Gaza Strip into southern Israel sharply decreased.