Every year around this time some Americans lament the fact that they've earned so much money; while others feel grateful they haven't earned more. April 15 is the deadline for filing federal income taxes in the United States, and Americans pay in proportion to what they earn, with wealthier citizens bearing a bigger share of the burden. As VOA's Nancy Beardsley reports, it's a system that's provoked heated debate for more than a century.

Linda de Marlor is a tax consultant in the Washington, D.C., area, whose job is to help clients calculate how much they owe in taxes to the U.S. Internal Revenue Service, or IRS. She's gotten used to dealing with strong emotions over the years.

"Some of the things you hear are, 'I hate the IRS,' and 'I'm going to send them all of my money in pennies,' things like that," she said, admitting that low-income taxpayers often have a different attitude.

"If you're a lower earning person like a single mom with a couple of kids, then you can take earned income credit, and a child tax credit, and you can take a deduction for child care expenses and things like that."

Does the system unjustly favor low income Americans, at the expense of the wealthy and the middle class? The debate revolves around two different definitions of fairness, says Steven Weisman, a New York Times editorial writer and the author of a new book called The Great Tax Wars.

"One is that it's only fair that the rich, who get the most benefits from society, pay proportionately more than others in their taxes," said Mr. Weisman. "But the other definition of society is, is it fair for people who work hard, save and invest, take risks, are the engines of our economy, to be in effect punished by having higher and higher tax rates the more they earn? And I believe we can see the virtue in both those ideas."

While popular sentiment has swung back and forth over the years, Steven Weisman says the basic nature of the argument hasn't changed. He's noticed parallels between the news stories he covers for the Times and the historical anecdotes he's found while researching his book.

"There was one point when I was writing about tax cuts or tax increases underway, and I was reading the debates going on in the House Ways and Means committee in 1862 and 1863," he recalled. "And I found Thaddeus Stevens, who was chairman of the House Ways and Means committee, and he was arguing about this in exactly the same language we were arguing about the last five years."

Steven Weisman says people have been paying taxes of various kinds since ancient times. And they've always been controversial. The American colonists rebelled against British rule partly because they were angry over taxes. But the great tax wars he focuses on in his book cover a 60-year period, beginning with the presidential administration of Abraham Lincoln in 1861, and ending with the Woodrow Wilson administration in 1920. He said Lincoln took office at a time when new sources of wealth were emerging.

"It wasn't until the Industrial Revolution that America moved away from being a farm-based, agrarian society to one where Americans earned money through wages and salaries, and investments and ownership of non-farm property, through businesses," noted Mr. Weisman. "And in the Civil War it was realized that the great emerging fortunes of America were owned by people who paid no tax on what they earned from them."

Until that time, import tariffs had provided the federal government with much of its revenue. But when the Civil War began in the 1860s, Steven Weisman said the government needed more money.

"The Union thought the Civil War was going to be a short affair, and they would be able to borrow everything because of this short war," he said. "Ironically, it was this bank that was lending money to the Union government that said, 'Wait, this war is going on longer than we thought. How are you going to repay this loan?' And that led to a debate in Congress about who should pay and to a levying on the income of the rich, many of whom had been getting even richer because of the war."

In the decades that followed, income taxes on America's wealthiest citizens would be imposed, dropped, then reinstated, depending on the prosperity of the nation. A constitutional amendment in 1913 established the basis for permanent income tax legislation.

"And by the end of World War I, the concept of taxing income was established after a bitter battle, and it was established to raise money to mobilize to fight a world war. Without war probably we wouldn't have had the income tax. Certainly rates wouldn't have been driven as high as they were during the war. Wars bring that out in society," concluded Mr. Weisman.

Income taxes were reserved for the wealthy until World War II. In 1939, only seven percent of the American labor force paid them. But by the end of that war, the figure had risen to 60 percent. And while it's now commonplace to complain about taxes, tax consultant Linda de Marlor believes Americans are better off than they realize.

She said when her immigrant clients file taxes for the first time, they're usually pleasantly surprised "first of all because our laws are very fair, and the tax rate is very low. In Italy there are 300 different taxes a store has to pay just on the kinds of advertising and signs it might have. Whereas in the United States if you have an expense, you can deduct it. Now we do have some who come from countries where there basically is no tax, especially the people who are self-employed, they don't really pay any taxes. So they get a rude awakening when they come here," she said.

Steven Weisman believes that if history is any guide, the expense of the Iraq war may launch new debates about taxes. But while Americans may never agree on the need for tax hikes or tax breaks, he is convinced the system itself is here to stay. "I think the idea that the wealthy should pay proportionately more in taxes is not a pleasant idea for us, but I don't think it will vanish," predicted Mr. Weisman, whose book, The Great Tax Wars, is published by Simon and Schuster.