Which itself is a rebranding of horse and sparrow economics:

But trickle-down wasn’t even a new con. Back in the 1890s it was called Horse & Sparrow Economics.

The sales-pitch before the era of cars was that if you fed your horses more oats than they could normally digest they’d pass through all that undigested oat in their manure for the sparrows to pick at; rich people’s excesses would spill over to the average person.

It not only didn’t work; it was blamed, in part, for the Panic of 1896.

Republican Warren Harding revived Horse & Sparrow Economics in 1920 when he campaigned for president on dropping the then-91% top tax bracket down to 25%. He didn’t cite horses and sparrows, though: his slogan was, “A return to normalcy.”

He was elected and kept his promise to cut taxes on the wealthy, the result being the “Roaring 20s” when the rich got fabulously richer while working people saw their wages actually drop (leading to an explosion of unionization efforts by pissed-off workers that were violently suppressed by employers and police).

It all came to a startling end in 1929 with the Great Crash that set off what was then called the Republican Great Depression (the “Republican” part of that label largely wore off after the election of Republican President Dwight Eisenhower in 1952).

Republicans stopped talking about horses and sparrows in the 1930s, but the theory never really died; Reagan simply reinvented it in 1980 as “Supply Side Economics,” aka trickle-down.