WTF?????. How? Working through the investment channel, boosting growth by 0.5%/year requires boosting the growth rate of the 60 trillion dollar capital stock by 1.5%/year, which requires a permanent one-time upward jump in investment of 4.5% of national income—of 900 billion a year. We are not getting that. Are there other channels Manki regars as "reaonable"? What are they?: Greg Mankiw: The Bad Economics Behind Trump's Policies: "One might reasonably argue that Trump’s tax cuts will increase growth over the next decade by as much as half a percentage point per year...

Gross Private Domestic Investment Nominal Potential Gross Domestic Product FRED St Louis Fed