At a Springfield, Illinois, event, some 20 years before the American Civil War, Abraham Lincoln delivered a prophetic message to his fellow citizens: "At what point then is the approach of danger to be expected? I answer, if it ever reach us, it must spring up amongst us. It cannot come from abroad. If destruction be our lot, we must ourselves be its author and finisher. As a nation of freemen, we must live through all time, or die by suicide."

The speech is said to be the origin of the popular quote wrongly attributed to Lincoln: "America will never be destroyed from the outside. If we falter and lose our freedoms, it will be because we destroyed ourselves."

While these were not Lincoln's exact words, most Americans understand that the 16th and 45th presidents of the United States were troubled by the same thing—the potential self-destruction of their nation.

History has demonstrated that internal discord can be as dangerous to a sovereign country as a foreign aggressor.

A History of Betrayal

In 2013, American author Diana West published "American Betrayal: The Secret Assault on Our Nation's Character." Her book initiated an important debate about the modern history of the American Republic.

Ms. West contended that Nov. 16, 1933, was the beginning of a long assault on the security of U.S. democracy. This was the date when Democrat President Franklin Delano Roosevelt decided to normalize relations with the murderous communist regime known as the Union of Soviet Socialist Republics. FDR's fateful decision opened America's doors to an unprecedented invasion of Marxist militants, communist spies, and domestic fellow-travelers.

In the decades that followed, progressive academics, journalists, novelists, artists, and entertainers all celebrated the socialist ideals of the Bolshevik Revolution. According to Ms. West, even American businessmen were "eager to buy their rope from Lenin."

Ms. West's views about the influence of communist ideologues in American politics were ridiculed by some of the most notable literary figures in the United States and Canada.