For the first time ever, according to Forbes magazine, the 400 richest Americanshave more than $2 trillion in combined wealth. And, a fifth of that amount is held by just 10 individuals. Of those top 10 richest Americans, six hail from two families—the Kochs and the Waltons—who are destroying our economy and corrupting our politics. We all should be outraged.

Arguably, the two most urgent tasks in this country are to transform our economy and to clean up our politics, and these two families stand in the way of both.

Our economy is addicted to fossil fuels and Charles and David Koch’s company,Koch Industries, is a key driver with investments in pipelines and refineriesacross the United States. These two Koch brothers rank four and five on the billionaire list.

In addition, our economy is marked by stagnating wages, which have sunk to povertylevels for millions of workers. The key driver of our low-wage economy is Walmart, with its 11,000 stores worldwide that pay so little that many of its workers get by on food stamps. The four main heirs to Walmart’s founder, Sam Walton, rank numbers six, seven, eight, and nine on the billionaires list. Three sit on the Walmart board, including Rob Walton, the board chair. (Other U.S. billionaires have made their fortunes in destructive Wall Street financial firms and through the generous government handouts of what President Eisenhower called "the military-industrial complex.")

The problem is, of course, not just economics. It’s the way that economics interacts with politics. The Koch brothers have poured some of their combined $72 billion in wealth into conservative and tea party politicians at the governor and state legislature levels.

And, they’ve financed a number of ultra-conservative state ballot initiatives. Scott Walker, for example, the Republican governor of Wisconsin, who gutted the state’s labor laws, is a major Koch client. And, the Kochs are big backers of the Keystone pipeline and stand to gain financially from its construction.

The Waltons—experts at tax avoidance—exercise a subtler, but equally corrosive, influence of our politics through their continued role in the world’s largest global corporation, Walmart.

Here is an example of how they operate. A year ago, Walmart announced it wanted to build six stores in Washington, D.C. This past summer, after a spiritedcommunity campaign, the D.C. City Council passed a resolution that would have required giant big box stores to pay a living wage. The day before the vote, Walmart very publicly announced that it would not build three of the stores if the resolution became law. The threat worked. The D.C. mayor vetoed the living wage bill.

By the way, the Kochs and Waltons aren’t the only top billionaires who are corrupting our politics. Number eleven on the list is Sheldon Adelson, who used his casino profits to shovel millions to Newt Gingrich and other conservatives in the 2012 elections. Numbers fifteen, sixteen and seventeen on the list are heirs to, and on the board of, Mars—the world’s largest candy maker. Mars has pouredmillions into lobbying the U.S. Congress to create an even more regressive, lessfair tax system.

What about liberal billionaires among the U.S. top 20? Yes, there are at least three among the top 20 who don't share the Walmart take on the world. Notable here are the top two on the U.S. billionaires list for the past decade: Bill Gates and Warren Buffett.

Both Gates and Buffett have steered tens of billions of dollars into philanthropy over recent years. Some of Gates’ dollars have funded wrong-headed policy initiatives on education, agriculture, and elsewhere.

However—and this is a big difference from the Kochs—neither has pumped large sums of money to intervene directly in U.S. politics or ballot initiatives. Lower down on the list at number 19 is George Soros, who has used his money to support liberal candidates and progressive nonprofits, but his $20 billion in wealth is dwarfed by the four Waltons' collective $136 billion and the Koch brothers’ collective $72 billion.

Unfortunately, the concentration of wealth in this country that these billionaires exemplify is increasingly mirrored in other countries. We examined the world’s 1,426 billionaires recently and chronicled the rapid rise of billionaires and inequality in China, Russia, India, Brazil, Hong Kong, Turkey, and elsewhere. Yet, the United States—with less than 5 percent of the world’s people, still hosts the most billionaires with 31 percent of the global total, and 12 of the top 20 (including the Kochs, the Waltons, and Adelson).

The primal scream of Occupy Wall Street in 2011 and 2012 was to end the ability of the 1 percent and giant corporations to crash our economy and corrupt our politics. Groups of the 99 percent like National People’s Action and the New Economy Working Group are among those leading the way toward a new economy rooted in shared prosperity, deeper democracy, and ecological balance. So too are groups like Public Citizen and Public Campaign leading the fight to separate corporation and state by getting big money out of politics.

These efforts deserve your outrage and your energy.