When pets are poisoned by imported pet food or U.S. attorneys are fired under suspicious circumstances, Congress gears up hearings and vows quick action. A far greater scandal, however, has hardly gained the interest of legislators or the presidential candidates. That is the increasing wealth gap between the rich, the middle class and the poor, which is reaching alarming proportions.

The top 10 percent of income earners in the United States now owns 70 percent...