Jeffrey Sachs is a professor and director of the Center for Sustainable Development at Columbia University . He is supporting Bernie Sanders for president. The opinions expressed in this commentary are those of the author; view more opinion articles on CNN.

(CNN) To judge how an economy is doing for its richest people, look at the stock market. To judge how it's doing for everyone else, look at life expectancy. These two measures show that America is coming apart at the seams: the stock market is booming while life expectancy has declined for three years running. Those in the top 1% , with incomes above $500,000 a year, are delighted; those in the working class are dying of what researchers have come to call "deaths of despair."

I am for one America, not two. Abraham Lincoln called for a "government of the people, by the people, for the people," -- not a government of the rich, by the lobbyists, for the few. We need policies that produce prosperity for all Americans, including guaranteed health care, decent wages and job benefits, a green new deal and 21st century infrastructure. The 2020 presidential election offers the most important choice our country has faced in generations. American democracy is at stake.

Donald Trump didn't create the divisions, but he is dramatically and willfully amplifying them. Our widening inequalities of wealth and resources can be traced to an infamous 1971 memo from lawyer Lewis Powell, Jr. to the US Chamber of Commerce. Powell wanted to put corporations into the political driver's seat. That same year Richard Nixon appointed Powell to the Supreme Court, and Powell soon put his plan into operation. In 1978, Powell wrote a disastrous decision ( First National Bank of Boston v. Bellotti ) giving companies free reign to spend corporate money in politics, under the preposterous doctrine that corporate spending on politics is merely free speech under the First Amendment.

Since then, the lobbies have eaten our democracy alive. The 2010 Supreme Court decision in Citizens United v. Federal Election Commission , which held that corporations and other groups can spend an unrestricted amount of money to promote candidates has massively exacerbated the problem. Since then, campaign funding through Super PACs and dark money

This contradicts what Americans want for our political system. By a huge margin, 77% to 20%, according to Pew Research Center data from 2018, Americans want limits on money in politics. Nonetheless, the Supreme Court opened the way for the corporate takeover of politics through massive campaign spending. In the future, the Supreme Court's campaign contribution decisions will be as infamous as the Court's reactionary decisions on slavery, separate but equal, and rejection of fair labor standards in the 19th and early 20th centuries.

Since the early 1980s, inequality in the US has soared . Starting with Ronald Reagan's 1981 tax cuts, the rates paid by the richest Americans have been slashed. Since then, repeated rounds of tax cuts have further benefited the rich . By 2018, the richest 400 Americans paid lower taxes as a share of income than any other income group including the poorest Americans, according to Berkeley economists Emmanuel Saez and Gabriel Zucman. The environmental movement , bipartisan at its start in 1969, was similarly derailed by big money in politics. Corporate lobbies have successfully pressured government officials to gut environmental regulations. America has gone from being the world's environmental leader to being the environmental rogue as Trump has pulled the US out of the Paris Agreement on climate change, the only country of the 193 UN member states to leave the accord.

And now big tech uses our personal data without proper protections of privacy and monetizes the data through online advertising and manipulations of e-commerce -- all the while getting the President and Congress to protect the sector from fair taxation and regulation.

The method of the corporate lobby takeover was anything but subtle. Their power is money. Over the years, these industries have contributed billions in campaign funds

They have spent billions more on lobbying outlays, some of which have employed former Congressmen and their families, in return for previous loyal support.

America's political system has been sold to the highest bidder. Consider some of the numbers from the 2018 election cycle. Oil and Gas spent $85 million on Congressional campaigns in 2018, of which 87% went to Republicans, and $126 million on lobbying, according to the Center for Responsive Politics. Health spent $265 million on campaigns, of which 56% went to Democrats and $568 million on lobbying.

According to recent survey data from NPR, Robert Wood Johnson Foundation and the Harvard T.H. Chan School of Public Health, a majority of people in the top 1% report themselves to be "completely" or "very satisfied" with life. No big surprise. Meanwhile, less than half of poorest Americans reported this same satisfaction. The same survey also shows that less than half of the top 1% believe that the federal government should prioritize narrowing the gap between rich and poor in the future, compared with a majority of low-income Americans. Another recent poll by Reuters and Ipsos shows a strong majority for taxing the wealth of the richest Americans.

No other high-income democracy has faced the corporate onslaught on national politics as has America. The result: America is falling behind our counterpart nations in the Organization for Economic Cooperation and Development (OECD) on almost all major social indicators. America's life expectancy now ranks 28th among the OECD countries

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As the other high-income countries amply prove, America's problems can be solved if our democracy can be retaken from the corporate lobbies and the big money in politics.

Bernie Sanders is running a true grassroots campaign, relying on more than 5 million individual donations so far to beat the big money. His movement harks back to the progressive era a century ago, when a similar grassroots movement successfully took on the power of the industrial robber barons of the late 19th century. Sanders' movement aims to wrest power from the corporate lobbies to reinvigorate our democracy -- and that is exactly what the country needs.

Politics this election year is therefore about the two Americas, the small group at the very top versus the common good. Trump brazenly stands on the side of the richest Americans. A true grassroots movement can restore fairness and prosperity for working Americans. The 2020 election is our urgent opportunity to retake power from the corporate lobbies and breathe new life into American democracy.