The article United States (People) traces this growth. It is closely connected with the first theme of E pluribus unum and the second theme of striving for greater democracy.The article details the variety of the U.S. population as it grew from natural increase and from immigration. More than that of any other nation in the world, the population of the United States has increased through repeated waves of immigration. Immigration gives the United States its typical character, and each wave of immigration changed the ethnic, racial, and religious composition of U.S. society. This variety provided a valuable mingling of cultures, but it has also been a source of tension and conflict, clouding the American promise of equality, freedom, and justice, and impeding the pursuit of E pluribus unum.

As the 20th century drew to a close, the majority of the U.S. population had achieved a high level of material comfort, prosperity, and security. Americans were not, prepared to cope with the unexpected problems of relative affluence or with the persistent difficulties created by residual pockets of poverty. Crime, racial conflict, urban decay, proliferation of nuclear weapons, pollution of the environment, drug abuse, and rising costs of living remained continuing subjects of concern.