I have followed this economic theory as I saw Trump seek advice from economists that support it. Much of it comes from Europe where liberals and labor unions fought the cuts in European government spending in "austerity" programs in places like Greece, Spain, and Italy to cut government borrowing and debt. The idea is austerity and spending cuts just cripple the economy so it never recovers. It is better to spend even more and incur bigger deficits and reduce taxes to spur growth-- print money-- in times of low interest rates, grow the economy and payback the debt as rates rise with economic growth. Ex Reagan economists ares speaking against this theory and do not support tax cuts now, because they only worked for Reagan when economic conditions were much worse than today-- as an example, they cite Bush's huge tax cuts made in a recovering economy that led to a recession. But in bad times, Obama kept Bush cuts and added more of his own which swelled the debt but spurred the recovery.