Following the creation of the Universal Declaration of Human Rights, Canada was perceived internationally as a strong ally in the protection of fundamental rights and freedoms. However, on a national level, Canadians had their own challenges.

Japanese internment camp located at Tashme, British Columbia, 1943.

"The War Measures Act remains on the statute books of this country. So long as it is on the statute books there is no reason why governments, if they so choose, might not create emergencies, real or apprehended, thereby permitting them to commit arbitrary acts under its powers."

(John Diefenbaker, House of Commons, 7 May 1946)

After the Second World War, controversy over the internment of Japanese Canadians before and during the war was brought to the forefront by the national press. Canadians of Japanese descent, mainly from coastal British Columbia, had been forcibly relocated due to fears of conspiracy with the Japanese Empire. Almost 23,000 people, three-quarters of whom were naturalized or native-born citizens, were removed from their homes and had their property auctioned, with the proceeds being retained by the government. Some male detainees were sent to work camps, while others were interned in prisoner of war camps. Using the War Measures Act, the Liberal government passed an order-in-council suspending habeas corpus, which resulted in citizens being imprisoned without charges having been laid.
Notice that appeared in Vanouver Sun and Vancouver Province Newspapers, 19 June 1942

As a Member of Parliament, Diefenbaker led the House Committee on the Defence of Canada Regulations. The Committee investigated instances where arrests and detentions without a trial occurred during the War. Diefenbaker strongly opposed Prime Minister Mackenzie King's decision to displace and intern Japanese Canadians. He argued that such decisions should be made through parliamentary debate, rather than by orders-in-council. In his view, only Parliament - not the Executive - had the right to legislate in a manner that violated civil liberties. (Parlimentary Democracy and the Canadian Bill of Rights - The Diefenbaker Legacy, 101)