Analysis of information sources in references of the Wikipedia article "United States presidential line of succession" in English language version.
If the Republican ticket had been elected in 1940, the plan of succession adopted in 1886 would probably have come into operation for the first time in 1944. Charles McNary, Republican candidate for Vice President, died on Feb. 25, 1944, With the death of Wendell Willkie, on Oct. 8, his Secretary of State would have been sworn in for the remainder of the term ending on Jan. 20, 1945.
If the Republican ticket had been elected in 1940, the plan of succession adopted in 1886 would probably have come into operation for the first time in 1944. Charles McNary, Republican candidate for Vice President, died on Feb. 25, 1944, With the death of Wendell Willkie, on Oct. 8, his Secretary of State would have been sworn in for the remainder of the term ending on Jan. 20, 1945.