First income tax is passed: The United States Congress passes the first income tax to raise revenues for the war effort. Although never enacted, it was an important fiscal innovation that paved the way for growth of the government in the 20th century.
I don't know if my reply actually applies here; but it has amazed me how much the debt increased from 7/1/1860 of $64,842,287.88 to $524,176,412.13 on 7/1/1862 and then on 7/1/1865 to $2,680,647,869.74 and 7/1/1866 to $2,773,236,173.69.
On 7/1/1867 the debt was down to $2,678,126,103.87.
I wonder how much, if any, of the wartime debt was reduced in the year and years after the war and just how much of the debt owed beginning after the war supposedly went to aid in rebuilding the South.