sentences:  The government continued to issue greenbacks and borrow large amounts of money, and the United States national debt grew from $65 million in 1860 to $2 billion in 1866.Congress passed the Revenue Act of 1864, which represented a compromise between those who favored a more progressive tax structure and those who favored a flat tax.The act established a five percent tax on incomes greater than $600, a ten percent tax on incomes above $10,000, and raised taxes on businesses.