Camp Merritt was activated for use in World War I. It was from there that many soldiers headed for war in Europe were deployed to Hoboken, New Jersey in order to be shipped off to Europe. Camp Merritt was decommissioned in November 1919. Fort Dix, in Pemberton Township, New Jersey, was also constructed to help in the war effort starting in June 1917. It was used as a training and staging ground throughout the war. After the end of the war, it was converted into a demobilization center.
In addition to camps for training soldiers, factories were needed desperately to produce ammunition to help the war effort. Four companies that produced ammunition were created during the World War I period: Atlantic Loading Co., Bethlehem Loading Company, DuPont Engineering Company, and T.A. Gillespie Loading Company. Around 1919, after the end of the World War I, these companies and plants slowed and ceased production of war materials. In addition, New Jersey became a leading chemical producer worldwide after discovering German secrets. Many chemical companies in New Jersey were able to exploit their advantage to become some of the largest chemical producers.
Like much of the rest of the United States, New Jersey entered a prosperous state through the 1920s. Through this period, New Jersey's population and employment rate increased greatly. Though factory production decreased after the end of World War I, production lines still remained in relatively high production.
Transportation became much easier through the 1920s. Cars became easily affordable and common. Roads were paved and improved greatly. As a result, many people who had never been farther than their hometown now could travel around the state. The Jersey shore became extremely popular through this period of time. The Benjamin Franklin Bridge was completed, linking Camden, New Jersey and Philadelphia, Pennsylvania in 1926. The Holland Tunnel, under the Hudson River, was completed in 1927 providing a means of easy transportation between New Jersey and New York City. Before, ferries were required to travel across the Hudson River. Later on, the George Washington Bridge (1931) and the Lincoln Tunnel (1937) were completed, making access to Manhattan even easier.
New Jersey was also the first state in the United States to ratify Prohibition, which restricted the purchasing and selling of alcohol. However, the Eighteenth Amendment to the United States Constitution, which banned alcohol consumption, was later repealed by the Twenty-first Amendment in December 1933. Newark's breweries reopened almost immediately.
In 1938 Orson Welles' produced his infamous The War of the Worlds radio broadcast from New Jersey. Listeners were told that a "huge, flaming object, believed to be a meteorite, fell on a farm in the neighborhood of Grover’s Mill, New Jersey, twenty-two miles from Trenton." It went on to describe extraterrestrial monsters that destroyed massive stretches of lands in New Jersey as well as massacring many people. Although it was announced in advance and at conclusion as a radio play, the broadcast resulted in widespread panic into New Jersey and the surrounding areas. Many people had believed the bulletin to be real, and that New Jersey truthfully was being torn up by giant and immensely powerful Martians. People fled the New Jersey area, while others worked hard to blockade their homes and ensure safety from the reported monsters. Listeners were relieved to discover at the end of the broadcast that it had been a fictional account. CBS was criticized for allowing fictitious bulletins to gain attention of listeners. Welles and the other broadcasters were not punished by law, but were held under a brief informal "house arrest" for a short period of time while being bombarded by questions by news reporters.
During the Great Depression, 20-month old Charles Augustus Lindbergh, Jr., son of famous aviator Charles Lindbergh, was abducted from his home near Hopewell, New Jersey. A long investigation ensued as detectives attempted to round up the kidnapper of the baby. The police proceeded to seal off many roads in order to prevent the kidnapper's escape, and interrogated the members of the Lindbergh household. The stress of being under police questioning led to the suicide of Violet Sharpe. Dr. John F. Condon became a negotiator between the kidnapper "John" and the Lindbergh family. The kidnapper demanded a ransom of $50,000, which was paid but turned out to be a hoax. Two other hoaxes were perpetrated by two other people who were not involved in the kidnapping, desperate to get their hands on ransom money. Both were charged after there declarations proved false. The baby was later found dead.
However, federal experts and detectives slowly managed to capture the kidnapper. James J. Finn was a lieutenant who tracked the ransom money. He had agents travel to banks to capture the kidnapper while passing the ransom bills. Meanwhile, Arthur Koehler, a federal expert, carefully examined the ladder used by the kidnapper. He traced the ladder to a company in McCormick, South Carolina. Finally, a ransom note was located and traced to Bruno Hauptmann; the bill had the license plate number of Hauptmann's blue Dodge Saloon that was written down by a gas attendant. He was tried in Flemington, New Jersey in what was known as the "Trial of the Century", and was convicted.
Bruno Hauptmann was electrocuted in the New Jersey State Prison in Trenton, New Jersey. As a result of the Lindbergh kidnapping the Federal Kidnapping Act, also known as the Lindbergh Law, was passed making kidnapping a federal law. The mystery novel Murder on the Oriental Express may have been based upon this kidnapping, with events paralleling many of the Lindbergh kidnapping.
In 1937 the German zeppelin Hindenburg exploded over Lakehurst, New Jersey. While approaching a mooring mast in Lakehurst, the zeppelin suddenly caught fire, and within 34 seconds the entire hydrogen-filled zeppelin was engulfed in flames; 36 people died in the disaster, most of them leaping from the burning ship. Contrary to popular belief, the Hindenburg had flown an entire year of successful voyages before it caught on fire. Questions and controversy surround the accident to this day: theories for the sudden burst of flames include sabotage against the German Nazis, static buildup, and flammable fabric.
Camp Kilmer was a staging area near New Brunswick serving the port of New York. Buildings were painted such that they had a camouflage effect. Camp Kilmer helped to serve troops by offering medical care and providing them with supplies. Camp Kilmer became inactive in 1949 but was reactivated for the Korean War. It again became inactive in 1955, but was reactivated for the 1956 Hungarian Revolution. Fort Dix was opened again for the training of soldiers for the war effort. Nearly 500,000 soldiers enlisted for the war, leading many women to take jobs in their husbands’ absences.
Millville Airport opened on August 2, 1941. It was called "America's First Defense Airport" because it was opened as a gunnery training area for fighter pilots. Over 1,500 pilots were trained for advanced aircraft fighting at this airport. Fort Hancock, New Jersey was also opened in Sandy Hook (New Jersey). Gunners in the fort prevented German submarines from entering New York Harbor.
An internment camp housing people of Japanese, German, and Italian descent was located in Gloucester City, New Jersey. In addition, Seabrook Farms, New Jersey took advantage of Japanese labor to increase productivity when the government allowed small groups of people from the internment camps to work there. At the end of World War II, the government closed down the internment camps, but many people from the camps continued to work at Seabrook Farms.
In 1947 the current version of the New Jersey State Constitution was ratified, reorganizing the state government. Governors were allowed to serve four years instead of three, and a bicameral Legislature was created, consisting of a 40 member Senate and an 80 member Assembly. The new State Constitution also returned the right of suffrage to females and blacks.
In 1947 the Trenton Six Case went to trial in Trenton, New Jersey. Six African American defendants were convicted by an all-white jury and sentenced to death for the murder of an elderly white shopkeeper based on coerced confessions.
In the early 1950s, the cities of New Jersey began experiencing urban decay. Governments attempted to intervent with the urban decay, focusing on the office Gateway Center and several other projects. However, suburbs continued to grow. Revolts occurred, often due to frustration about the poor urban conditions. As urban decay started a gap between the wealthier suburbs and poorer cities, state income taxes were implemented to stop the gap. Around the 1970s, urbanization started increasing again.
During the 1960s, many African Americans felt disenfranchised. This feeling was exacerbated by police forces, which often sided against African Americans. This tension led to race riots, the first of which occurred in Jersey City on August 2, 1964, causing heavy damage to the Jersey City area. 71 stores were damaged and 46 people were injured. From August 11 to August 13, 1964, similar riots occurred in Paterson and Elizabeth. In the Paterson riot, twenty stores and other buildings were damaged, and eight people were injured. In the Elizabeth riot, six people were injured and seventeen stores were damaged. In the aftermath of these riots, 135 people were arrested. In the middle of the Cold War from June 23 to June 25, 1967, president Lyndon Johnson met with Soviet premier Aleksei Kosygin in Glassboro, New Jersey at the Glassboro State College. No specific agreements were reached, especially in the area of restrictions on anti-ballistic missile systems. However, the meeting helped improve the strained relationships between the Soviet Union and the US.
Also in the summer of 1967, urban residents, primarily African Americans, rioted for 5 days in Newark and the neighboring city of Plainfield. The cause was the feeling that African Americans were being disenfranchised. 24 people died in the riots, and nearly 1,600 were arrested. The riots are often cited as a major factor in the decline of Newark and its neighboring communities, as many residents fled to the suburbs following the riots.