Thanks to the economic crisis of 1957-61, the U.S. economy entered the decade of the 1960s with high levels of unemployment and excess capacity. The millions of unemployed workers and idle plants and machines meant that industrial production could increase rapidly in response to rising demand.
Since supply was increasing almost as fast as demand, prices rose very slowly. At least according to the official U.S. producer price index, prices hardly changed between 1960 and 1964.
As is typical of the phase of average prosperity of the industrial cycle, long-term interest rates rose very slowly. Still, at around 4 percent or slightly higher they had risen significantly since the Korean War days. Back then, the Truman administration still expected to borrow money long term at less than 2.5 percent. Slowly but surely long-term interest rates were eating into the profit of enterprise.
The 1960s economic boom begins
During most of the early 1960s, the U.S. economy was passing through the phase of average prosperity that precedes the boom. But starting in 1965, the industrial cycle entered the boom phase proper.
The transition from average prosperity to boom is part of the industrial cycle. However, in the mid-1960s this transition was helped along by government economic policies. These were, first, the Kennedy-Johnson tax cut of 1964 combined with the rapid escalation the war against Vietnam. After remaining virtually unchanged through 1964, the official U.S. producer price index suddenly surged 3.5 percent in 1965. That was the year the escalation of the Vietnam War began in earnest.