The richest families in America are paying less in taxes than the rest of the country for the first time ever, a new book claims.

“For the first time on record, the 400 wealthiest Americans last year paid a lower total tax rate — spanning federal, state and local taxes — than any other income group, according to newly released data,” columnist David Leonhardt wrote in a column published earlier this week, citing a new book titled “The Triumph of Injustice,” written by liberal economists Emmanuel Saez and Gabriel Zucman.

The book takes aim at President Donald Trump’s tax cuts, the signature legislative achievement of his presidency. The 2017 “Tax Cuts and Jobs Act” spurred significant economic growth and led to a booming stock market, but critics have contended that the bill did not do enough to help middle class families. (RELATED: Our Tax Code Treats Corporations Better Than Families)

Taxes on high-income Americans have declined dramatically in the last half-century. The U.S. had the world’s highest tax rates at 91% for high-income earners in the 1950’s and early 1960’s. Now the top tax bracket sits at 37% for those making over $500,000 a year. Meanwhile, Americans who earn the median income of roughly $48,000 a year are still giving away nearly a quarter of their income to the federal government. Leonhardt says that the narrowing of the gap has increased inequality in the U.S. (RELATED: Biden’s First Move As President? Kill The Trump Tax Cuts)

Leonhardt also says that rich families have taken advantage of loopholes to pay even less than a quarter of their income in taxes, and paints Trump’s tax cuts as a giveaway to special interests who have a disproportionate amount of influence in the nation’s capital.

“The overall tax rate on the richest 400 households last year was only 23 percent, meaning that their combined tax payments equaled less than one quarter of their total income,” he writes.

Many of those families have formidable political operations that they use to fund lawmakers’ campaigns. This includes the Kochs, the Adelsons, the Waltons, George Soros, and many others, who don’t live in Washington D.C., but whose influence is still felt throughout political circles in the nation’s capital.

Washington elites who have used their money to gain influence, and who benefited the most from the tax cuts include Commerce Secretary Wilbur Ross and Steve Case, a local billionaire who served as a member of President Barack Obama’s “Council on Jobs and Competitiveness,” and whose political work has primarily focused on immigration reform.

Other influential Washington billionaires include Washington Redskins owner Dan Snyder, and Washington Capitals owner Ted Leonsis, a former Obama critic who recently decided to become more involved in politics. Amazon CEO Jeff Bezos, the richest man in the world, also owns a home in D.C., and has made donations to various liberal political causes, and likely saved hundreds of millions of dollars due to the Tax Cuts and Jobs Act. Amazon also paid $0 in federal taxes last year, despite raking in a profit of $11.2 billion.

Democrats have sought to frame the tax cuts on the campaign trail as a giveaway to the richest Americans, and a betrayal of the president’s populist base. Democratic House Speaker Nancy Pelosi has repeatedly referred to the tax cuts working families received as “crumbs,” and some 2020 presidential candidates have promised to make repealing the tax law an early priority if they’re able to take the White House next Fall.

Trump himself has said that he’s considering additional “various tax reductions,” aimed at helping the middle class.