Distant Early Warning Line

United States-Canadian military

Also known as: DEW Line

Written and fact-checked by The Editors of Encyclopaedia Britannica

Distant Early Warning Line (DEW Line), Cold War communications network, made up of more than 60 manned radar installations and extending about 4,800 km (3,000 miles) from northwestern Alaska to eastern Baffin Island. The network served as a warning system for the United States and Canada that could detect and verify the approach of aircraft or intercontinental ballistic missiles (ICBMs) from the Soviet Union.

Those installations, which were constructed by the U.S. military on remote Arctic tundra beginning in 1954, were manned around the clock by U.S. and Canadian military personnel as an extension of the North American Air Defense Command (NORAD). The DEW Line was coordinated with several similar radar detection networks, such as the Pinetree Early Warning Line (which spanned the width of southern Canada near the 49th parallel), the Mid-Canada Line (which spanned the width of Canada at the 55th parallel), and the U.S. Navy’s Atlantic and Pacific Barrier, as well as air and sea patrols and radar stations in Iceland, Great Britain, the Faroe Islands in the North Atlantic, and Greenland. The first phase of the DEW Line became operational on July 31, 1957, and the line was expanded to encapsulate the Aleutian Islands and Greenland by 1961.

The DEW Line and other early-warning installations were effective deterrents against Soviet aggression during the Cold War. The Soviets knew that any air strike launched by them would be detected early enough that the U.S. Air Force could destroy most of their incoming bombers or ICBMs with fighter interceptors. The Soviets also knew that they would suffer considerable retaliation by the U.S. Strategic Air Command, whose airborne nuclear-armed bombers could be expected to survive the first strike.

The DEW Line grew out of a study in the early 1950s by scientists at the Massachusetts Institute of Technology (MIT), who found that the United States and Canada were vulnerable to a Soviet air attack from across the North Pole. The U.S. communications company Western Electric, which was controlled by AT&T, was awarded the contract to facilitate construction of the line. More than 25,000 workers, many of them subcontractors, built radar sites, roads, towers, airplane hangars, residences, and antennas in the most sparsely populated region of North America.

By the mid-1980s, aging facilities, improved technologies (such as the Airborne Warning and Control System [AWACS]), and advanced detection systems, together with the diminished threat of Soviet aggression in the waning years of the Cold War, led to the demise of older early-warning systems such as the DEW Line. Starting in 1985, the DEW Line system was replaced by the North Warning System, and many of the original DEW Line sites were abandoned or dismantled.

This article was most recently revised and updated by John P. Rafferty.

NORAD

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NORAD

Also known as: North American Aerospace Defense Command, North American Air Defense Command

Written by André Munro

Fact-checked by The Editors of Encyclopaedia Britannica

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In full:: North American Aerospace Defense Command

Headquarters:: United States; Colorado; Colorado Springs

Related People:: Lori Robinson

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NORAD, binational military organization involving the United States and Canada. Established in 1957, with a formal agreement signed in 1958, NORAD is tasked with providing aerospace warning and control—and, since 2006, maritime warning—for the defense of North America. It is headquartered at Peterson Space Force Base in Colorado and maintains regional bases in Alaska (Joint Base Elmendorf-Richardson), Manitoba (Canadian Forces Base Winnipeg), and Florida (Tyndall Air Force Base). NORAD’s commander is a U.S. military officer, and the deputy commander is a Canadian military officer, but both are appointed by and accountable to both countries’ governments.

NORAD, a product of the Cold War, was until the early 2000s primarily focused on external threats posed by rival state actors. Since the United States recognized that its defense strategy could not exclude Canadian territory, partnering with Canada allowed the creation of a truly continental defense structure against foreign threats, especially the Soviet Union. Canada’s aim was not only to bolster its own defense but also to assert its sovereignty against the United States. Through its “defence against help” strategy, Canada saw NORAD as a means to prevent unilateral territorial encroachment by its powerful southern neighbour.

The September 11, 2001, attacks in the United States had a significant effect on NORAD’s mission and operations. Following the terrorist attacks on New York City and Washington, D.C., NORAD’s defense activities turned inward with Operation Noble Eagle, a domestic military operation that aimed to protect strategic sites, such as cities and crucial infrastructures, and to escort suspicious aircraft. These attacks also led to the expansion of air alert sites, from which armed and ready fighter jets could take off at any moment; the number of these sites had declined from 26 at the fall of the Soviet Union to 7 by September 11, 2001. Soon thereafter, the number of alert sites increased to more than 30, though it has since been reduced.

Despite NORAD enduring the test of time and the end of the Cold War, American and Canadian views and priorities for homeland defense have not always aligned. Their strategies notably diverged on the question of ballistic defense systems. Although NORAD was, from its founding, mandated with the aerial defense of the continent, its operation did not include countermeasures against incoming ballistic missiles beyond detecting such threats. Antiballistic initiatives, such as U.S. Pres. Ronald Reagan’s short-lived Strategic Defense Initiative (SDI; often referred to as the Star Wars initiative), were solely U.S projects.

NORAD’s relevance, as well as the American dedication to NORAD’s binational framework, was called into question in October 2002 with the United States’ creation of the U.S. Northern Command (USNORTHCOM), whose official mandate overlapped with that of NORAD in many respects. Since then, the commander of NORAD has also held the position of commander of USNORTHCOM. Canada followed suit by creating a similar integrated command of its own, known as Canada Command from 2006 to 2012, after which it merged with other commands to form the Canadian Joint Operations Command (CJOC). Despite these developments, both countries remain committed to NORAD’s existence and in 2006 renewed their underlying agreement without expiration.

André Munro