The United States is currently the world's oldest democracy.

But America is no more immune from collapse than were some of history's most stable and impressive consensual governments. Fifth-century Athens, Republican Rome, Renaissance Florence and Venice, and many of the elected governments of early 20th-century Western European states eventually destroyed themselves, went bankrupt or were overrun by invaders.

The United States is dividing as rarely before. Half the country, mostly liberal America, is concentrated in 146 of the nation's more than 3,000 counties — in an area that collectively represents less than 10 percent of the U.S. land mass. The other half, the conservative red states of the interior of America, is geographically, culturally, economically, politically and socially at odds with blue-state America, which resides mostly on the two coasts.

The two Americas watch different news. They read very different books, listen to different music and watch different television shows. Increasingly, they now live lives according to two widely different traditions.

Barack Obama was elected president after compiling the most left-wing voting record in the U.S. Senate. His antidote, Donald Trump, was elected largely on the premise that traditional Republicans were hardly conservative.

Currently, some 27 percent of all Californians were not born in the United States. More than 40 million foreign-born immigrants currently reside in the U.S. — the highest number in the nation's history. 

Yet widely unchecked immigration comes at a time when the country has lost confidence in its prior successful adherence to melting-pot assimilation and integration. The ultimate result is a fragmenting of society into tribal cliques that vie for power, careers and influence on the basis of ethnic solidarity rather than shared Americanness. ...