LBJ used the Vietnam War to prop up the Stock Market. There is a 36 year cycle, in the Anglo American world—in Britain since 1821, in America at least since 1857. Note the crash sequence 1857, 1893, 1929! The market topped out at 1000 in December 1965, but LBJ being savvy and totally corrupt, deliberately masked the 1929 reprisal by inflating the money supply via “guns & butter,” at the same time. The hapless Jummy Carter paid the price for what followed in the late 1970s, which was only arrested by the ridiculously high interest rates engineered by Paul Volcker.
There’s a number of cycle theories in economics. Kitchin cycle, Juglar cycle, Kuznets swing, and Kondratiev wave among them. They aren’t deterministic, much to the chagrin of many market timers. Johnson owes a good deal of the prosperity of his time to the Kennedy tax cuts, deficit spending, and Europe still rebuilding.
Eisenhower, Kennedy, Johnson, and Nixon failed to address the Triffin Dilemma and Nixon junking Bretton Woods gave us the inflation of the 70s. Nixon and Carter both employed price controls. Reagan wisely adopted the supply side ideas which Democrats Lloyd Benson and Russell Long had been toying with in the Carter years.
https://www.independent.org/pdf/tir/tir_07_3_roberts.pdf