You may have heard there's a presidential campaign going on. One of the favorite lines of attack by Democrats against Republicans is the idea of "trickle-down economics." It goes something like this: Republicans believe in trickle-down economics, trickle-down economics is bad, thus Republicans are bad. That was basically the content of Barack Obama's attacks on Mitt Romney in 2012 (he did make an easy target), and Hillary is fond of reprising the cliché on Twitter and on the stump. Now, "trickle-down economics" is a term of abuse used to refer to "supply-side economics." But the two are actually vastly different from one another.