Shortly after Donald Trump took office in 2017, we noted that while most of the social-media comments he and his media team post are politically calculated, even when caustic, some of those posts are net losers that undermine his agenda.

This week, in what amounts to unfortunate timing — but an entirely avoidable error — at 0145 Tuesday morning, Trump (or one of his social-media minions) posted the following statement about the sentencing of Roger Stone: “This is a horrible and very unfair situation. The real crimes were on the other side, as nothing happens to them. Cannot allow this miscarriage of justice!”

That statement was correct. And Trump has rightly argued about sentencing before, especially in regard to those who have been caught up in dragnets because he and his administration have clearly been the targets of unjust investigations seeded by deep-state actors.

Unfortunately, once again, after the administration’s best week on record, Trump has unwittingly derailed some of that momentum with an unforced error.

For the record, last week was the best of any for the Trump administration. On Monday, Gallup reported that Americans are very optimistic about our country. Tuesday, the president delivered an outstanding State of the Union Address to Congress. Wednesday, he was acquitted on both articles of impeachment, dispensing with the Democrats’ impeachment charade. Thursday, Democrats were in full panic mode about Bernie Sanders and Trump’s increased prospects for reelection. Friday, the administration’s week ended with a stellar jobs report.

But this week, a careless social-media post has diverted attention from that great week.

As it turns out, Attorney General William Barr, the administration’s strongest right-thinking advocate for Rule of Law, had already determined that he would seek a reduction of Stone’s sentencing after his conviction for lying to investigators and obstructing Congress. According to The Wall Street Journal, “Senior Justice officials had concluded on their own that the sentence recommendation was excessive and had decided to rescind it before Mr. Trump’s tweet.”

Then came Trump’s most egregious error: After becoming aware of Barr’s plan, he doubled down on his assertion about Stone’s sentencing. Trump has the power to pardon Stone, commute his sentence, etc. He should have let this play out and get out of Barr’s way.

In effect, Trump unintentionally set up Barr for criticism, and the latter lamented, “Once [Trump’s comment posted], the question is, now what do I do? Do you go forward with what you think is the right decision or do you pull back?”

Predictably, Democrat Party leaders and their Leftmedia publicists immediately claimed that Trump and Barr were colluding on the Stone sentencing. They demanded the resignation or (yes) impeachment of Attorney General Barr.

For his part, Barr rightly rebuked Trump for his carelessnesses: “I think it’s time to stop the tweeting about Department of Justice criminal cases. I’m not going to be bullied or influenced by anybody … whether it’s Congress, a newspaper editorial board, or the president. I’m gonna do what I think is right, and you know, to have public statements … made about the department, about our people in the department, our men and women here, about cases pending in the department, and about judges before whom we have cases, make it impossible for me to do my job and to assure the courts and the prosecutors in the department that we’re doing our work with integrity. I cannot do my job here at the department with a constant background commentary that undercuts me.”

Sen. Mitch McConnell backed Barr: “The attorney general has said it’s making it difficult for him to do his job. I think the president ought to listen to the attorney general. … The president made a wise selection in picking Bill Barr. I think he ought to listen to him. … I think the attorney general knows what he is talking about. … I think he’s told the president this is not helpful, making it difficult for him to do his job. I think the president ought to listen to him.”

Responding on Trump’s behalf, White House Press Secretary Stephanie Grisham insisted Trump “wasn’t bothered by [Barr’s] comments at all and he has the right, just like any American citizen, to publicly offer his opinions.” She added, “President Trump uses social media very effectively. … The president has full faith and confidence in Attorney General Barr to do his job and uphold the law.”

Memo to Stephanie: Nobody is questioning the “right” of Trump to post comments on social media. We question the wisdom of those comments. This was not an example of “using social media very effectively.” It was an example of using social media very carelessly.

Moving forward, the real test of whether President Trump is capable of a modicum of teachability will be if he takes Barr’s advice, as indeed he should — a cease and desist regarding pointless distractions from his administration’s extraordinary successes and future agenda. Hopefully, having been challenged by Barr, he will not be so “bothered” that he insults Barr, as he has with other former administration officials who have been loyal to him and their oaths “to support and defend” our Constitution.