As military experts debated the range and lethality of North Korea’s latest and most successful launch of an intercontinental ballistic missile; on the day the Senate would vote to begin consideration of a once-in-a-generation tax reform; as two crucial federal judicial nominees tried to fight off the culture-war attacks of Sen. Dianne Feinstein, D-Calif., and the abortion lobby; where was President Trump?

Keeping himself busy with other matters on Twitter.

Most people sometimes goof off on social media when they should be working. But Trump's tweeting isn’t a matter of procrastination or picking petty battles. This is the president ignoring the difficult and pressing challenge of pressing his policy agenda forward, and instead pouring out divisive invective on subjects beyond his purview.

Specifically, the president scapegoated religious and ethnic minorities and attacked the news media, every politician's favorite foe.

Trump’s retweets on Wednesday morning were indefensible. “VIDEO: Muslim migrant beats up Dutch boy on crutches!” the first one read. “VIDEO: Muslim Destroys a Statue of Virgin Mary!” was the second one. “VIDEO: Islamist mob pushes teenage boy off roof and beats him to death!” the third.

The White House’s attempt to justify these tweets, which may or may not accurately have described the videos, did not hold water. “Whether it’s a real video, the threat is real and that is what the president is talking about,” spokeswoman Sarah Sanders told reporters Wednesday.

There are many legitimate ways to talk about the very real threat of radical Islamism or of inadequate border control that don’t use unreliable and unstable Twitter personalities or paint an entire religion as murderous. Trump never tried to tie these problems to any policy, foreign or domestic. The end product of this performance appears to have been to divide his own country and scapegoat minorities.

This is appealing to some voters and it infuriates news media and is thus a cheap, cheap win for Trump that has nothing to do with his job, and in fact, undermines his ability to do it.

His tweets about the news were perhaps less pernicious, but there were just as pointless. He peddled a conspiracy theory about a murdered congressional staffer to attack MSNBC’s Joe Scarborough. He also called for the firing of NBC’s chairman and a boycott of CNN.

The public doesn't have much sympathy for news media, which it holds in nearly as low a regard as it holds Congress. Many Republican voters see most of the biggest media outlets as members of the opposition, or resistance, to Trump. So the president's Twitter rhetoric probably warms a few hearts. But it is ultimately futile, for Trump has no authority over NBC, or any other news media, which is as it should be.

So Trump spent Monday morning ignoring issues over which he has control — taxes, containing North Korea, and confirming judges — but that are difficult and involve dedication and heavy lifting. Instead, he focused his attention, and thus much of the media’s attention, on issues over which he has little or no control, but which involve little risk because he's merely picking squabbles and launching baseless insinuations that will win him points with a small segment of his base.

Events this week are stark reminders that the world is dangerous and that the office of the presidency is a serious one that should not be taken lightly as if it were a platform for Trump's atrocious social media habits.