” In 1980 revenues to the US treasury were around $500B annually.”
You may remember that the economy was in the tank and interest rates were up to 22% in 1980 and for a time thereafter. I remember that very well as I left the firm I had been with for 4 years and hung out my own shingle. My wife was my secretary and was typing until 5:00 pm the evening she went into labor with our first son. We got by in some measure by bartering because no one had any money. It wasn’t a good time economically. By ‘88, things had gotten rather dramatically better.
Congress did do the spending under Reagan. It has under Obama too.
Laffer was correct, it is just common sense.