The national debt in 2000 was $5.7 trillion and in 2017 it was $20 trillion. What are the three main reasons for expansion in debt?

Tax Cuts, War in Iraq and Afghanistan and Protectionism

Explanation:

US has an increasing debts and is the largest country having a huge amounts of debts. The reason behind it is Trump's isolation policy. Imports are reduced and incomes are low therefore to overcome the crisis US is taking loans. The next reason is the wars in Afghanistan and Iraq which has cost the economy of US very much. Tax cuts also plays an important role in this field because as the government cuts the taxes it must pay it by itself increasing the debts from other countries.

Answer: tax cuts, increases in military spending, and recessions