Consider some facts: the 400 wealthiest Americans have more money than the bottom 50 percent of all Americans combined. Between 1979 and 2007, the incomes of the top 1 percent of the population grew by 275 percent while the incomes of the middle class rose only 40 percent. And according to newly released measures, a staggering one in three Americans, or 100 million people, suffer in poverty or near poverty.

These are startling facts, and the Occupy movement, with its references to “the 1 percent” and “the 99 percent,” has brought them to the fore of public consciousness. In response some critics have argued that the popular protest against inequality is inspired by mere envy, or an effort to inflame class warfare. We disagree. Inequalities can—in this case do—raise ethical concerns, and we think citizens are right to be outraged at the gap between the 1 percent and the 99 percent. We seek here to explain why these inequalities are so troubling.

But first, let us say the obvious: inequality in itself is not always wrong. Some inequalities are both inevitable and desirable. In a market economy, we expect inequalities of income. More generally, a world in which there were no differences between people is hard to imagine: we are unequal in so many ways. Some work harder, some are more talented, some are more comfortable with taking risks. American society has always recognized that there can be legitimate reasons for rewarding people unequally. Therefore it is important to ask what forms of inequality are morally objectionable.

A great diversity of objections to inequality can be raised. Three of them concern opportunity, civic status, and fairness. The United States, and all liberal democracies, need to pay attention to these concerns.

Defending equality is based on the democratic imperative to create a community where every citizen has a fair chance at a decent life.

Vast economic inequalities are incompatible with genuine opportunity and social mobility for all. Yet the idea of equality of opportunity enjoys wide acceptance in the United States. It is the core of the American Dream. But social mobility in America is lower today than a generation ago. The accident of birth is highly predictive of one’s life chances; people increasingly occupy fixed and frozen positions and pass these positions down to their children. In other words, children born into poor families tend to stay poor and children born into wealthy families generally stay rich. By contrast, intergenerational mobility today is greater in Canada, France, Germany, and the Scandinavian countries.

The growing income and wealth gaps also create unequal citizenship, a second source of objection. Very large differentials in income translate into systematic advantages: in political influence, access to jobs and positions of authority, health, personal security, and the opportunity to develop one’s talents. When unequal wealth can systematically purchase advantage in each of these domains, it is difficult to face each other as social equals. As inequality has grown, the fate of the few has become unhinged from the fate of the many, as the wealthy find security in cloistered neighborhoods, send their children to private schools, and attend sporting events in luxury skyboxes. Divided from one another, our unequal lives no longer reflect the fact that society depends on the productive contributions of us all.

We worry about the general effects of massive income and wealth differentials, but we want to call special attention to its effect on politics. In a democracy, equal citizenship is foundational: every citizen has a vote and only one vote. But when money is speech and corporations are persons, and when politicians depend on contributions for election, the 1 percent speak with megaphones and the rest of us with a whisper. It is only when the 99 percent assemble that a people’s microphone is possible.

Finally, the canyon between the 1 percent and the 99 percent is not the result of a fair process, where the rules and rulers of the game are equally responsive to the interests of all persons. Some inequalities are justified by the manner in which they came about. But the inequalities in life prospects of Americans today are the result of laws and institutions that cater to the very rich and have ceased to be responsive to the vast majority. Tax burdens on the wealthy have dropped to the lowest rate in many decades. Loopholes abound so that corporations can post enormous profits but escape taxation altogether. Corporate lobbyists have massive influence on the rules of the game, while the wealthy disproportionately influence the political process and disproportionately win elected office. It is no surprise then that our tax policies and campaign-finance laws are not a product of, and do not reflect, the interests of most Americans.

The result? A society riven by lack of genuine opportunity, unequal civic status, and systematic unfairness. For us, defending equality, and objecting to the outrageous inequalities between the 1 percent and the 99 percent is based on the democratic imperative to create a community where every citizen has a fair chance at a decent life, an equal opportunity to develop their talents, and an equal voice in political decisions. This aspiration for a society of equals finds its taproot not in envy or class resentment but in our country’s founding ideals and in the democratic dreams of peoples everywhere.