As protests are usually linked to economic crises, the US GDP (see chart below from Forbes magazine) is a good subject to start with. The period 1965-1970 was characterised by plummeting GDP ending in the 1970 recession. Growth picked up post-1970 especially after Nixon broke the fixed link between the US dollars and gold in August 1971. Two years later, it dropped again as a result of the oil price surge following the OPEC embargo. The surprising thing is that there have been no widespread protests since despite the occasional episodes of falling GDP, in some cases much worse than the late 1960s. That is, till now.
President Johnson's spending on the Vietnam war and Great Society - mainly Social Security and healthcare - started to creep up from 1966. However it was the expansion of credit for business corporations and households that had been fueling the economy prior to Johnson's escalated spending. As inflation inched up in 1966, the Fed raised the Fed funds rate to 5.76% by November 1966, slowing the economy in the process though Johnson's public spending prevented the economy from falling into recession.
The impact can be seen in the money supply measure, the best being the total credit market debt (see chart below) instead of the generally accepted M1, M2 or M3. In 1966, 1968 and 1969, the total credit relative to GDP was lower compared to the three years preceding 1966. This was the primary cause of the 1970 recession much as the contraction in 1960-61 had contributed to the recession of those years.
But the economic difficulties were not evident from the unemployment rate as seen in the misery index (see chart below). Yet the inflation rate was increasing despite the slowdown in debt growth. Obviously there must be something that had been constraining capacity reducing its ability to match the debt growth, even though now subdued.
Remember that during this time the US was still having a current account surplus (see right panel of the chart below from The Economist), albeit with a declining rate, so the foreign countries couldn't have supplied the goods either to meet the demand from the higher money supply.
Even the US industrial production was running above capacity throughout the second half of the 1960s (see graph below from The New York Times). So goods and services supply were tight, thus the inflationary conditions. But inflation couldn't have been the main culprit since in later years under Gerald Ford's and Jimmy Carter's watch, during which the protests no longer resurfaced, the inflation rate was much worse.
The 1960s was also the beginning of the fourth Kondratieff wave. It would have been impossible for the growth drivers (computers and internet) of this wave to have kicked in at such an early stage. After eliminating all suspects, we are left with only one. It is the one that enabled the US to get out of the economic doldrums of the late 1960s and early 1970s. But its contribution has not been given the credit to which it richly deserves. It is the increased female participation in the labour force. And the driver that enabled the women to enter the labour force in great numbers was electricity, the main engine of the third Kondratieff wave.
Electricity-enabled home appliances which began to enter the market in 1930s to 1950s allowed women to have more free time. So by the mid-1960s, the women started to enter the labour force in large numbers to supplement the income of their spouses. But the overall impact was felt only from the 1970s since the inclining women labour force participation rate (LFPR) outweighed the declining male LFPR only then (see graph below). As household income increased, the urge to protest declined.
The impact of the roughly 8% higher LFPR was significant, not only because the productive capacity increased but also the consumption ability grew. However after the drivers of the fourth Kondratieff wave entered the economy in a big way - computers in the 1980s and internet in the 1990s - the LFPR began to flag. The new drivers make it possible to run operation with a greatly reduced number of workers than before. Globalisation worsened the already bad situation. Capacity swelled as foreign countries became part of the supply chain. Initially inflation was a scourge because certain commodities, in particular oil, had a lag of 7 to 10 years to come onstream. Well the new oil fields are now ready to be tapped at a time money supply is fast shrinking with massive debt write-offs. The world will be awash with cheap goods but bereaved of money.