Heather Cox Richardson is a professor of history at Boston College and the president of the Historical Society. The opinions expressed are her own

The government has the right to “demand” 99 percent of a man’s property when the nation needs it.

That was the argument made by a Republican congressman in 1862 to introduce a novel idea: the federal income tax.

The Civil War was then costing the Treasury $2 million a day. To pay for uniforms, guns, food, mules, wagons, bounties and burials, Congress had issued hundreds of millions of dollars of bonds and paper money. But Republicans had a horror of debt and the runaway inflation that paper currency usually caused.

Taxes were the obvious answer. A conservative Republican newspaper declared: “There is not the slightest objection raised in any loyal quarter to as much taxation as may be necessary.”...