Lyndon B. Johnson's first year as president was one for the history books: it began with President Kennedy's assassination on Nov. 22, 1963, and ended almost exactly a year later with Johnson's reelection to the White House, in a major victory over controversial Republican candidate Barry Goldwater.
That year is the subject of All the Way, premiering on Saturday night on HBO and starring Bryan Cranston as LBJ. LIFE Magazine was tracking the real thing as it was happening; that reelection was the subject of a Nov. 13, 1964 cover story about the "Mighty Landslide." And, though the published issue would only include a couple of shots of the President and his family at their Texas ranch, LIFE's photographer John Dominis captured the whole run-up to Johnson's learning that he had won handily—and how he celebrated.
Despite the eventual results and Johnson's well-founded confidence, it was clear that the President wouldn't consider the victory his until the results were official. And even then, one of American history's biggest landslides wasn't entirely satisfying.
"He wants," a friend told LIFE before the results came in, "to make it unanimous."