Enemies at home: attacks and spies on the US home front in WWII

"Let 'em come… V Homes are Ready!" An Office of War Information billboard, about 1942–45. National Archives (NAID 514856).

Pearl Harbor was not the only place in the United States the enemy reached. By 1945 Japanese forces had attacked the mainland and nearly every American territory in the Pacific, and occupied several of them; German submarines sank ships within sight of American beaches; and spies for Germany, Japan, the Soviet Union and even Britain worked across the country. At home, civil defence volunteers learned to recognise aircraft by sight and sound, enforced blackouts and took first-aid courses. Elsewhere in the "Greater United States", civilians lost their homes and their lives.

Attacks from the sea

The Atlantic. Once the United States was in the war, German U-boats hunted merchant ships along the East Coast and in the Caribbean, to cut Europe off from American supplies and American industry off from raw materials. Within eight months they had sunk hundreds of ships and millions of tons of cargo.

• Some coastal resort towns, afraid of losing tourists, ignored blackout orders — and ships silhouetted against the lights were easy targets. Some went down close enough to shore for people on the beach to watch.
• Fearing losses, the United States stopped shipping food, supplies and fuel to Puerto Rico, and stopped importing its products, rum among them. The island's economy was crippled.
• Attacks nearly stopped once cargo ships sailed in armed convoys, from 1942.

The Pacific.

Civilians on Wake, Guam and in the Philippines who survived the invasions lived under occupation with forced labour, eviction, separated families, starvation, imprisonment, torture and execution — and more were killed as American forces fought to take the islands back.

The balloons

Between November 1944 and April 1945 Japan launched more than 9,000 Fu-Go balloons carrying incendiary and anti-personnel bombs into the newly discovered jet stream — the first intercontinental weapon of modern times. About 300 reached North America, some as far east as Michigan. They started forest fires and briefly cut power to the Manhattan Project. In Oregon, one killed six people who found it on a picnic — the only deaths from enemy action on the mainland.

Spies

Germany. U-boats landed at least ten agents. In June 1942 four came ashore on Long Island and four in Florida with money and explosives to sabotage war production; in 1944 two landed in Maine and reached New York City before the FBI caught them. Many more German agents had lived in the country for years, some as naturalised citizens, including crew on the SS America collecting information as it passed through the Panama Canal Zone. Between 1938 and 1942 the FBI broke up at least four German spy rings and charged 51 people, turning some into double agents.

Japan. Before the war, two former U.S. Navy men — Yeoman Harry T. Thompson and Lieutenant Commander John S. Farnsworth — sold secrets to Japan. In Honolulu, Takeo Yoshikawa, under cover at the Japanese consulate, reported on the fleet's movements before Pearl Harbor, using the Pan American Clipper landing at Pearl City as one lookout and working with a German agent in Hawaiʻi. The German was caught and convicted; Yoshikawa had left in a diplomatic exchange before anyone discovered what he had done. No person of Japanese ancestry living in the United States was convicted of serious espionage or sabotage during the war — but at least ten white Americans were convicted as Japanese agents, among them Velvalee Dickinson, a New York doll dealer who coded ship movements as doll repairs in her letters.

The Soviet Union. An ally from June 1941, it still ran as many as five spy rings in the United States, with agents in the military, the federal government, the Manhattan Project and jet-fighter programmes.

• William Weisband, a linguist in the Army's "Russian Section" of codebreakers at Arlington Hall, was not unmasked until 1950.
• Julius and Ethel Rosenberg were executed at Sing Sing in 1953 for passing atomic secrets; Ethel's guilt remains disputed.
• Morris and Lona Cohen, who carried atomic-bomb information to the Soviets, escaped; arrested years later in Britain, they ended their lives in the Soviet Union after a prisoner exchange.

Army Signal Intelligence Service codebreakers at Arlington Hall, Virginia, about 1943. U.S. Army.

Britain. British agents worked with the government's grudging blessing — and behind its back, through an intelligence office in New York, to push the country into the war. The FBI meanwhile trained with them in espionage and counter-espionage.

What came next

Attacks on American soil and the presence of enemy agents fed fear, and the response to that fear — incarceration, martial law — is its own chapter of the home front.

Sources

Written from "The American Home Front During World War II: Enemies on the Home Front", by Megan E. Springate for the National Park Service Cultural Resources Office of Interpretation and Education, part of the series The American Home Front and World War II.