Question: James Patrick Aylward, was a Missouri attorney, Democratic party leader, and a political associate of Harry S. Truman, he was the 33rd President of the United States (1945–53), assuming that office upon the death of Franklin D. Roosevelt during the waning months, of which historic event?
Context: USS "Harry S. Truman" (CVN-75) is the eighth "Nimitz"-class aircraft carrier of the United States Navy, named after the 33rd President of the United States, Harry S. Truman.  The ship's callsign is "Lone Warrior", and she is currently homeported at Naval Station Norfolk, Virginia. The first inauguration of Harry S. Truman as the 33rd President of the United States was held at 7:00 pm on Thursday, April 12, 1945, in the Cabinet Room at the White House in Washington, D.C., following the death of President Franklin D. Roosevelt earlier that day.  The inauguration marked the commencement of the first term (a partial term of ) of Harry Truman as President. Lieutenant General Louis Watson Truman (June 20, 1908 – December 2, 2004) was the former Commanding General of Third U.S. Army.  General Truman was cousin to 33rd President, Harry S. Truman, and served as his Aide-de-Camp during President Truman’s inauguration in 1948. Harry S. Truman (May 8, 1884December 26, 1972) was the 33rd President of the United States (1945–53), assuming that office upon the death of Franklin D. Roosevelt during the waning months of World War II.  He is known for launching the Marshall Plan to rebuild the economy of Western Europe, for leading the Cold War against Soviet and Chinese communism by establishing the Truman Doctrine and NATO, and for intervening in the Korean War.  In domestic affairs, he was a moderate Democrat whose liberal proposals were a continuation of Franklin Roosevelt's New Deal, but the conservative-dominated Congress blocked most of them.  He used the veto power 180 times, more than any president since then, and saw 12 overridden by Congress; only Grover Cleveland and Franklin D. Roosevelt used the veto so often, and only Gerald Ford and Andrew Johnson saw so many veto overrides.  He is also the only world leader to have ever used nuclear weapons in war, desegregated the U.S. Armed Forces, supported a newly independent Israel, and was a founder of the United Nations. James Patrick Aylward (September 10, 1885 – July 22, 1982) was a Missouri attorney, Democratic party leader, and a political associate of President Harry S. Truman. Truman Day is a commemorative holiday to celebrate the birth of Harry S. Truman, the 33rd President of the United States.  It is celebrated May 8 in Missouri as a state holiday, according to Missouri Revised Statutes Section 9-035 Public Holidays and nationally by the United States Democratic Party.  Since Truman was the only president to come from Missouri, this day is special for this state.  However, after the financial crisis of 2008-2010, there were unsuccessful moves by the state government to abolish the holiday.  For Missouri state employees, this is a paid holiday. The Harry S. Truman Presidential Library and Museum is the presidential library and resting place of Harry S. Truman, the 33rd President of the United States (1945–1953), located on U.S. Highway 24 in Independence, Missouri.  It was the first presidential library to be created under the provisions of the 1955 Presidential Libraries Act, and is one of thirteen presidential libraries administered by the National Archives and Records Administration (NARA). The 1950 State of the Union Address was given by Harry S. Truman, the 33rd President of the United States, on Wednesday, January 4, 1950.  He spoke to the 81st United States Congress, to the United States House of Representatives and the United States Senate.  It was a joint session, and the 160th address given.  He said, "Our aim for a peaceful, democratic world of free peoples will be achieved in the long run, not by force of arms, but by an appeal to the minds and hearts of men."  He also said, "Our Social Security System should be developed into the main reliance of our people for basic protection against the economic hazards of old-age, unemployment, and illness." The Harry S Truman Birthplace State Historic Site is a state-owned property in Lamar, Barton County, Missouri, maintained by the Missouri Department of Natural Resources, preserving the 1 ⁄ -story childhood home of Harry S. Truman, the 33rd President of the United States.  The future president was born here on May 8, 1884, in the downstairs southwest bedroom.  The home was purchased by the state in 1957 and dedicated as a historic site in 1959 at a ceremony attended by Truman himself. Electoral history of Harry S. Truman, 33rd President of the United States (1945–1953), 34th Vice President of the United States (1945) and United States Senator from Missouri (1935–1945)
Answer: World War II