“Donald Trump is the first president in my lifetime who does not try to unite the American people—does not even pretend to try. Instead, he tries to divide us.”

—U.S. Marine Corps Gen. (Retired) James Mattis

Back when James Mattis served our nation a defense secretary, I along with many other observers, noted that he emerged immediately as the rare grownup serving in the Cabinet in the Donald Trump administration.

Then he got fired. Why? Because he differed with Trump on a whole array of defense and foreign policy decisions.

His highly critical assessment of Trump, delivered in this widely circulated quote, speaks volumes about what Gen. Mattis saw up close during his time as defense secretary.

Tragically, Trump is campaigning for re-election as president by continuing to divide the nation. He is campaigning exclusively to the base of voters who propelled him to the White House by virtue of the Electoral College majority he eked out over Hillary Rodham Clinton.

For the ever-lovin’ life of me I don’t understand how this process is supposed to work as he fights for re-election in a campaign against Joseph R. Biden Jr. Trump’s approval rating stands in the low 40 percent range. The average of public opinion polling puts Biden up by about 8 to 9 percent. The former vice president figures to get a big bump from the virtual Democratic National Convention that convenes Monday.

Trump is going to campaign for re-election by telling us about all the ills that continue to plague the nation. But … wait a minute! Didn’t he declare that “I, alone” can solve those woes? Hasn’t he served as our chief executive for nearly four years? Didn’t he pledge to “drain the swamp” and “make America great again”?

Instead, Trump is going to proceed according to the Mattis Mantra that the retired Marine Corps general identified earlier this year. He will try to divide the nation he pledged to unite.

Go figure.