Consider that Secretary of State Rex W. Tillerson, until recently the chief executive of Exxon Mobil, ranks as a man of only middling wealth, with disclosed assets in the $400 million range. By contrast, Wilbur L. Ross, the distressed-asset investor and commerce secretary nominee, is worth more than $2.9 billion, according to Bloomberg. Steven T. Mnuchin, the secretary of the Treasury, is so rich that he neglected to account for about $100 million in assets on a disclosure form because of what he called an “unintentional” oversight.

That Mr. Mnuchin overlooked perhaps $100 million is unfathomable for many people. It is, in fact, roughly equivalent to the total net worth of more than 1,200 typical American families. And $1 billion is more than 12,000 of those households, according to the Federal Reserve Survey of Consumer Finances of 2013.

It found that the median American household had a net worth of $81,200.

What’s more, it said, the bottom 25 percent of the population had no net worth at all, in dollar terms: When household debt was included, the net worth of these families was less than zero. And along racial lines, the wealth gap was preposterous: The median net worth of black families was only $11,030 compared with $134,230 for whites, according to an analysis of Federal Reserve data by the Urban Institute.

For people of all races, the gap between the very rich and everyone else has been expanding in recent years, and not only in the United States.

A report by the charity Oxfam last month, for example, found that the richest eight billionaires on the planet, led by Bill Gates, the founder of Microsoft, were worth more than half of all of the people on earth. Yet one in every 10 of the world’s people, the report found, must get by on less than $2 a day.

“Inequality is trapping hundreds of millions in poverty; it is fracturing our societies and undermining democracy,” said Winnie Byanyima, executive director of Oxfam International.

My father died in September 2015, a month before his 93rd birthday, while the presidential primary campaign was still underway. Income inequality was a big issue. In his insurgent campaign on the Democratic side, Senator Bernie Sanders focused on it directly. Despite his wealth, Mr. Trump addressed it too, indirectly, promising to restore lost jobs and prosperity to downtrodden Americans. And perhaps he will accomplish that.