This is how it goes these days.

Less than a week ago, after Donald Trump tweeted a deeply personal, classless attack against two cable-news personalities, it seemed that we had reached an embarrassing new low point in presidential behavior, a level of crassness that even Trump himself might be challenged to beat. That seemed particularly true after evidence surfaced that Trump had attempted to use the National Enquirer to blackmail those two personalities into providing more positive coverage.

Silly, silly me for thinking that Trump couldn’t top that performance.

Over the weekend, Trump retweeted a doctored video that shows him decking and repeatedly punching a figure labeled CNN. Such a message, at a time of rising concern over the use of violence as a political tactic, coming from the person of the president himself, is just mind-boggling. It’s true: When Trump is attacked, he strikes back 10 times as stupidly.

Trump’s supposed target in all this is of course the media, but that’s not where his campaign is doing the most harm. Over the years, the presidency has been occupied by its share of incompetents, hacks, rakes and crooks, but throughout it all the office itself has survived untainted. Trump is in the process of destroying the aura of the presidency, demeaning it as an institution respected by Americans of all political ideologies.

And because the American president is viewed as the embodiment of the country that elects him, Trump is doing the same to the country as a whole. Every few years, the Pew Research Center surveys citizens of 37 nations about their attitudes toward the United States and world leaders. According to its research, 64 percent of citizens in those countries had a favorable view of the United States at the end of the Obama presidency; after a few months of Trump, that has fallen to 49 percent.

Under Obama, 64 percent of the developed world also had confidence that the U.S. president would do the right thing in world affairs. Today, 22 percent have such confidence in the U.S. president. Notably, the dropoff is most profound in those nations that in the past have been most closely aligned to the United States. In Germany, confidence in the president dropped 75 points; in Great Britain it dropped 57 points.

Two nations reported greater confidence in Trump than in Obama. In Israel, that increase was 7 percentage points. In Russia, it was an astounding 42 percentage points. Overall, both Russian President Vladimir Putin and Chinese President Xi Jinping have higher confidence ratings than Trump.

That represents an almost-catastrophic decline in American “soft power,” in our capability to influence world affairs on our behalf without turning to force of arms. Through Trump’s antics, we are in the process of forfeiting global leadership, with politicians around the world fleeing from association with the American president and thus with America itself.

Some Americans may attempt to dismiss such findings by boasting that they’d rather have a president who was feared by other nations than one who is respected or liked. That’s nonsense. To the degree that our allies fear Trump, they fear him in the way that you would fear a five-year-old waving a loaded pistol in a crowded room.

To make matters worse, Trump shows no capacity for change, and Republican leaders who assured us during the campaign that they would be able to constrain Trump have proved feckless in confronting him. I don’t know what we’re going to do about this.