Timeline of United States military operations in the context of "National Guard (United States)"

Operation Inherent Resolve (OIR) is the United States military's operational name for the international war against the Islamic State (IS)—a group also known as the Islamic State of Iraq and Syria (ISIS), the Islamic State of Iraq and the Levant (ISIL) or its Arab acronym "Daesh"—including both a campaign in Iraq and a campaign in Syria, with a closely related campaign in Libya. Through 18 September 2018, the U.S. Army's III Armored Corps was responsible for Combined Joint Task Force – Operation Inherent Resolve (CJTF—OIR) and were replaced by the XVIII Airborne Corps. The campaign is primarily waged by American and British forces in support of local allies, most prominently the Iraqi Security Forces (ISF) and Syrian Democratic Forces (SDF). Combat ground troops, mostly special forces, infantry, and artillery have also been deployed, especially in Iraq. Of the airstrikes, 70% have been conducted by the military of the United States, 20% by the United Kingdom, and the remaining 10% being carried out by Australia, Belgium, Canada, Denmark, France, Jordan, the Netherlands, Saudi Arabia, Turkey, and the United Arab Emirates.

According to the Pentagon, by March 2019, the day of IS's territorial defeat in Syria, CJTF—OIR and its partner forces had liberated nearly 110,000 square kilometers (42,471 square miles) of land and 7.7 million people from IS, the vast majority of the self-proclaimed caliphate's territory and subjects. By October 2017, around the time of IS's territorial defeat in Iraq, CJTF—OIR claimed that around 80,000 IS militants had been killed by it and its allies (excluding those targeted by Russian and Syrian air strikes). By the end of August 2019, it had conducted 34,573 strikes. Tens of thousands more were killed by partner forces on the ground (the SDF alone claimed to have killed 25,336 IS fighters by the end of 2017).

Democracy promotion, also referred to as democracy building, can be domestic policy to increase the quality of already existing democracy or a strand of foreign policy adopted by governments and international organizations that seek to support the spread of democracy as a system of government. In practice, it entails consolidating and building democratic institutions.

International democracy promotion typically takes three forms: assistance, monitoring, and conditionality. In financial terms, democracy promotion grew from 2% of aid in 1990 to nearly 20% in 2005. More controversially and rare, it can also take the form of military intervention.

Infrared homing is a passive weapon guidance system which uses the infrared (IR) light emission from a target to track and follow it seamlessly. Missiles which use infrared seeking are often referred to as "heatseekers" since infrared is radiated strongly by hot bodies. Many objects such as people, vehicle engines and aircraft generate and emit heat and so are especially visible in the infrared wavelengths of light compared to objects in the background.

Infrared seekers are passive devices, which, unlike radar, provide no indication that they are tracking a target. That makes them suitable for sneak attacks during visual encounters or over longer ranges when they are used with a forward looking infrared or similar cueing system. Heat-seekers are extremely effective: 90% of all United States air combat losses between 1984 and 2009 were caused by infrared-homing missiles. They are, however, subject to a number of simple countermeasures, most notably by dropping flares behind the target to provide false heat sources. That works only if the pilot is aware of the missile and deploys the countermeasures on time. The sophistication of modern seekers has rendered these countermeasures increasingly ineffective.