Iconfess a fondness for Harry S. Truman, some of it based on admiration of the conventional kind, some of it perhaps best described as cosmically circumstantial. I was born in Washington, DC, less than two miles from the White House then occupied by Harry Truman. While I don’t go in for astrology, I still like to think of Harry (and Bess, too) as constituting my own political zodiac sign. He is my guide to good sense and hence the herald of my good fortune (such as it is, and may become).

Truman’s own fortune, historically speaking, did not come quickly or easily. He came to the presidency in tragedy following Franklin Delano Roosevelt’s death in April 1945, and FDR’s act was about as hard for Harry Truman to follow as Lincoln’s was for Andrew Johnson. Yet Truman somehow won the 1948 election despite not one but two defections from his own party (Henry Wallace to the Progressive Party Left and Strom Thurmond to the Dixiecrat Right). Shortly thereafter, however, his popularity fell off sharply when he asked a weary citizenry to accept new burdens at home and abroad. He left office during the Korean War with a 23 percent approval rating, the lowest ever since those kinds of data have been kept.

But as everyone also knows—not least George W. Bush and his diminished coterie of loyal supporters—Truman’s reputation has soared over time as his judgments have been vindicated. Harry Truman’s Administration is widely credited with having conceived the basic strategy and raised up the key institutions, domestic and international, that in due course won the Cold War. That assessment is basically true, too, though it took the Eisenhower Administration to consolidate that path and the Reagan and George H.W. Bush Administrations to collect the laurels.

President Truman was a man of bold strokes—from the August 1945 decision to drop two atomic bombs on Japan to the June 1950 decision to resist Communist aggression in Korea to the April 1951 decision to fire General Douglas MacArthur. But three decisions he made in-between these others, all in the spring and summer of 1948, just as surely stand out for their boldness and their beneficial consequences.

On May 12, 1948, against the advice of all his military and diplomatic advisers, Truman decided to recognize without delay the new state of Israel. Had it not been for that decision, Israel would have had a much more difficult time overcoming the odds against its successful birth.

At a June 26, 1948, cabinet meeting, once more against the advice of nearly all his advisers, Truman backed the resolution of General Lucius Clay,...