This piece is by the conservative organization, Prager University (not to be confused with the forthcoming Kruse Kollege.) It does a nice job describing the Laffer Curve, an important concept to know if you want to have an informed debate about tax policy. Clearly the presenter is trying to persuade you about the location of a hump in the Laffer Curve. Even if you dispute his pinpointing of the hump, the presence of a hump is real.
