If the Trump administration has one overarching goal, it’s to Make America Great Again. But what does this mean? It means we are promoting MAGAnomics—and that means sustained 3% economic growth.

For most of our nation’s modern history, a healthy American economy meant one that grew at roughly 3.5%. That was the average growth rate between the late 1940s and 2007. Since then, it has hardly topped 2%.

The...