Trump's proposal to close the American economy to foreign goods by imposing tariffs would kick off a global trade war, slowing down economic growth and increasing unemployment. Retaliations from countries such as China and Mexico would result in new tariffs and lower American exports to those countries, reducing economic activity. Higher interest rates in the US along with uncertainty around a potential global trade war would drive up the cost of the dollar, making all American exporters less competitive in the global market.
In 2016 Moody's Analytics suggested that if Trump were elected president and put his stated policies into practice, the United States would experience a lengthy recession, enormous job losses, much higher interest rates and diminished long-term growth prospects.
Tax cuts and larger deficits cause an economic contraction in the long run, and largely benefit only the rich. Over time tax cuts would lead to higher government deficits, eventually pushing interest rates up and crowding out other economic activity in the economy.
Mass deportation would create a negative shock to the supply side. Trump's proposal to deport millions of undocumented immigrants would reduce the nation's economic output as there would be fewer workers in the US. Employers would struggle to fill these vacancies and many employers are reliant on cheaper immigrant labour.