There are many ways to create economic suicide on a national level. The major way through history has been through indebting the economy. Debt always expands to reach a point where it cannot be paid by a large swathe of the economy. This is the point where austerity is imposed and ownership of wealth polarizes between the One Percent and the 99 Percent.
Trump's claims that he's making taxes more democratic for the people, but it actually is a vast sucking of income and wealth upward.