THAT’S BECAUSE OBAMA WAS A TERRIBLE PRESIDENT: The Obama years, which left us divided and angry, paved the way for the ascent of Donald J. Trump.

Start with the economy. It’s true that he inherited a wicked recession, that unemployment is much lower than when he entered office and that the stock market has reached an all-time high. On the flip side, the economic recovery has been unusually weak, with annual growth never exceeding 3 percent. (Until Mr. Obama, every president since Herbert Hoover had at least one year of 3 percent growth.) The labor force participation rate is at the lowest it has been since the 1970s. Since 2008, real wages have remained the same or fallen for the bottom four-fifths.

To make matters worse, the Obama presidency has been characterized by injurious incompetence, in particular with regard to his signature achievement, Obamacare. The unveiling of the website was a disaster, and the promises the president made — that Americans could keep their doctors and plans if they chose to — were false. Mr. Obama guaranteed lower insurance costs to families and lower health costs to the taxpayer; instead, costs rose. Several of the state-run exchanges appear to be headed for collapse.

Overseas, the Obama years have been defined by spreading disorder and chaos, particularly in the Middle East and North Africa, with nations collapsing and borders dissolving. More terrorist safe havens have been established than ever before. Russia and China have become more aggressive and significantly increased their geopolitical influence. America is now held in brazen contempt by our enemies and mistrusted by many of our allies.

Yet in some respects the greatest failure of the Obama years is in the area where many people thought he would excel. Mr. Obama made the centerpiece of his 2008 campaign a promise to end a politics that “breeds division and conflict and cynicism.” In February of that year, I praised him for “a message that, at its core, is about unity and hope rather than division and resentment.” Yet he leaves office with America more conflicted and cynical than when he took office. More than 70 percent of Americans say the country is either more divided or no more united than it was in 2009. Race relations are the worst in decades, and our nation is as polarized as it has been in the modern era.

I wonder how many pieces like this will have to appear in the New York Times before the wall of denial collapses.

Plus:

Yet Mr. Obama never seemed to consider things from a different point of view from his own. He has shown withering disdain for his opponents, constantly impugning their motives even as he testified to the purity of his own. It was his arrogance that proved to be Mr. Obama’s undoing. (Even leaders of his own party felt Mr. Obama’s derision, as if dealing with them was somehow beneath him.) Mr. Obama dismissed those who disagreed with him like a professor forced to deal with simple-minded, wayward students.

And that arrogance and contempt, even more than his other failures, brought on Trump. Choose the form of your Destructor!