“Equal opportunity for all” has been the essence of the American Creed for 250 years.

Why, then, do we remain so blind to the inequalities that persist in our country – the sexism reflected in recent harassment scandals; the racism dramatized by the fact that black incarceration rates for drug offenses are 5.5 times higher than those of whites, even though the same percentage of blacks and whites use drugs; the glaring economic inequality that is rapidly defining our society.

As we embark on a new year, it is time we wake up to not only the ways we are betraying our nation’s highest ideals, but why this is happening.

One reason for this blind spot might be our psychic need to feel good about who we are as a people. Another could be our unwillingness to face up to the degree to which we are becoming one of the most unequal economic societies in the world.

The complicated economic history of America speaks directly to that issue. Slavery dominated the political economy of the South until the Civil War, sharecropping and tenant farming thereafter, while commerce, farming and industrialism shaped the North.

With urbanization, new industries and massive immigration, social turmoil grew. The Settlement House Movement and the Progressive Era at the end of the 19th century ameliorated some of the economic injustices that plagued the new economy, creating minimum-wage and maximum-hour legislation for women, and labor laws for children.

But then, during the 1920s, inequality spread. Wages remained stagnant as profits grew. Soon, the Great Depression occurred, creating a crisis of a depth and breadth never seen before.

In response, Franklin Roosevelt’s New Deal created a set of social welfare programs to stabilize a society in chaos – Social Security, unemployment benefits, the Works Progress Administration. But the economy did not come back until World War II. Only then, with massive military mobilization, unprecedented wartime production and revolutionary technological breakthroughs, did the economy take off.

World War II ushered in the multi-decade era of prosperity that helped create the “affluent society” of the 1950s and ’60s. The GI Bill and Veterans Administration housing subsidies allowed millions to go to college and purchase houses – homeownership increased from 40 percent of Americans in 1940 to 60 percent in 1960. Suburbs blossomed across the land; interstate highways mushroomed. With the civil rights movement in the ’50s and ’60s, new opportunities for blacks and women emerged. Some suburbs started to desegregate. Black college enrollments expanded 500 percent by the late ’70s. A new black middle class emerged.

At the same time, the War on Poverty diminished the percentage of Americans living beneath the poverty line, even though the Vietnam War soon took much of the money originally intended to fight poverty.

Meanwhile, the middle class continued to grow, and income levels conflated, so that by 1979 the top 1 percent of income earners took home only 8 percent of the national income – a dramatic reduction from the 1920s and ’30s.

What we have too often ignored is the degree to which this process has been turned on its head over the last 35 years. The share of national income earned by the top 1 percent has more than doubled since 1979. The top 1 percent now make 81 times as much as the bottom 50 percent, whereas in 1980 it was 27 times as much.

As a consequence, the total household wealth of the top 1 percent of the population has gone from 7 percent in the late ’70s to 22 percent in 2012, which is slightly less than the total wealth of the entire bottom 90 percent.

These figures highlight the degree to which we have reversed the progress achieved from 1941 to 1979, and are quickly returning to the chaos of the late 1920s. America, in the words of United Nations poverty expert Philip Alston, is becoming “the world champion of extreme inequality.” The latest tax “reform” bill simply hastens the process.

That is hardly the fate envisioned by those who founded a nation based on equality of opportunity. But it will be our destiny unless we change course soon.