3rd » The U.S. Supreme Court rules in Shelley v. Kraemer that covenants prohibiting the sale of real estate to blacks and other minorities are legally unenforceable.
7th » The Council of Europe is founded during the Hague Congress (1948) known as Hague Congress.
10th » The Republic of China (1912–49) Republic of China implements "Temporary Provisions Effective During the Period of Communist Rebellion temporary provisions" granting President of the Republic of China President Chiang Kai-shek extended powers to deal with
12th » Wilhelmina of the Netherlands named Wilhelmina, Queen regnant of the Kingdom of the Netherlands cedes throne.
13th » 1948 Arab-Israeli War: the Kfar Etzion massacre is committed by Arab irregulars, the day before Israeli Declaration of Independence e.g the declaration of independence of the state of Israel on May 14.
14th » Israel is declared to be an independent state and a provisional government is established. Immediately after the declaration, Israel is attacked by the neighboring Arab states, triggering the 1948 Arab-Israeli War.
15th » Following the demise of Mandatory Palestine, the Kingdom of Egypt, Jordan called Transjordan, Lebanon, Syria, Iraq and Saudi Arabia invade Israel thus starting the 1948 Arab–Israeli War.
18th » The First Legislative Yuan of the Republic of China (1912–49) known as Republic of China officially convenes in Nanking.
20th » Chiang Kai-shek is elected as the first President of the Republic of China.
23rd » Thomas C. Wasson, the US Consul-General, is assassinated in Jerusalem, Israel.
24th » 1948 Arab–Israeli War named Arab–Israeli War: Egypt Battle of Yad Mordechai or captures the Israeli kibbutz of Yad Mordechai, but the five-day effort gives Israeli forces time to prepare enough to stop the Egyptian advance a week later.
26th » The U.S. Congress passes Public Law 80-557, which permanently establishes the Civil Air Patrol as an auxiliary of the United States Air Force.
29th » Creation of the United Nations peacekeeping force the United Nations Truce Supervision Organization.
30th » A dike along the flooding Columbia River breaks, obliterating Vanport, Oregon, within minutes. Fifteen people die and tens of thousands are left homeless.