There was formal censorship during World War I, WWII and the Korean War. At the beginning of WWI Robert Borden’s government passed the War Measures Act. Hundreds of pacifists and antiwar activists were arrested under an Act that allowed “censorship and control and suppression of publications, writings, maps, plans, photographs, communication and means of communication.” A June 1915 order-in-council established a Chief Press Censor’s Office empowered to prohibit media. With the approval of the Secretary of State, Chief Censor Colonel Ernest Chambers was authorized to block any news sources “assisting or encouraging the enemy, or preventing, embarrassing or hindering the successful prosecution of the war."
At its high point 120 postal employees helped the Censor’s Office keep an eye out for “unpatriotic” materials. The posties were empowered to open suspicious letters — generally those not in English or French — and report their contents.
Chambers quashed a number of films, plays and records. “In the last months of the war,” notes Mark Bourrie, “the censors began poking through record stores and demanded catalogues from the major US record companies. Thirty-four records were banned, all of them foreign language songs.”
Beyond individual books, films and records, the Censor’s Office banned 253 news sources. The vast majority of them were from the US, which stayed neutral until late in the conflict. The censored publications were generally in foreign languages and a good number of them promoted some variant of Marxism. With the War Measures Act remaining in force until January 1920, the censor banned dozens of socialist reviews after the Armistice was signed in November 1918.
During WWII the media’s pro-war bias made it largely unnecessary to suppress information, but the government gave itself that stick. The Defence of Canada Regulations stated: “No person shall a) spread reports or make statements intended or likely to cause disaffection as to His Majesty or to interfere with the success of His Majesty’s forces or of the forces of any allied or associated Powers or to prejudice His Majesty’s relations with foreign powers; b) spread reports or make statements intended or likely to prejudice the recruiting, training, discipline, or administration of any of His Majesty’s forces; or c) spread reports or make statements intended or likely to be prejudicial to the safety of the State or the efficient prosecution of the war.”
At its high point the Department of National Defence's Directorate of Censorship oversaw nearly 1,000 employees who mostly opened mail. More than 45 million letters and packages were opened during the war.
A dozen publications were banned during WWII and at least three corporate dailies —Vancouver Sun, Le Droit and Le Soleil — were fined for breaching censorship regulations. Many books were also banned and a number of dissidents jailed.
During the Korean war of 1950-53 journalists in the field operated under strict censorship. Soon after the war began the US-led UN force warned that “unwarranted criticism of command decisions or of the conduct of Allied soldiers on the battlefield will not be tolerated.” Six months into the war the UN command produced censorship criteria, which further restricted journalists. Reporters were not permitted to discuss casualties or allied air power, nor employ the word “retreat” to describe the UN’s ejection from North Korea. In effect, they weren’t allowed to criticize UN forces.
Any attempt to bypass the censors or defy the rules in other ways could result in court-martial or removal from the theatre. In the first ten months of the war at least 17 international journalists were expelled.
On one occasion Canada’s external minister complained UN censorship was not more robust. Lester Pearson was angry when the New York Times reported on a North Korean village hit by US napalm. The story noted, “the inhabitants throughout the village and in the fields were caught and killed and kept the exact postures they had held when the napalm struck … There must be almost two hundred dead in the tiny hamlet.”
In a letter to the Canadian ambassador in Washington, Hume Wrong, Pearson wondered how the article might affect public opinion and complained about it passing censors. He wrote, “such military action was possibly ‘inevitable’ but surely we do not have to give publicity to such things all over the world. Wouldn’t you think the censorship which is now in force could stop this kind of reporting?”