As with the departure of her mentor, former White House chief of staff Gen. John Kelly, the exit of Kirstjen Nielsen as secretary of homeland security is cause for regret.

Nielsen resigned from Homeland Security Sunday, with a polite resignation letter and a courteous Twitter sendoff from President Trump.

It didn't really make sense, because she did a capable, competent job in a complex, difficult position, particularly on border security.  The press is reporting that President Trump wanted more in the way of results, which is reflective of his hotel manager temperament, described so well here.  There is a crisis on the border as millions of illegals — and not just from Central America anymore — and the criminals they are supposedly fleeing from prepare to flood the U.S. southern border.

Nielsen wasn't awful.  She displayed a capable, competent dedication to the mission, never insulting us, never going into Bush-era "compassion" for illegal aliens to send mixed messages from the country's top law enforcement body on the border.  She was somewhat creative, as government officials go, in attempting to halt the flow from the Central American side of things, as well as through Mexico.  She was also competent on disaster relief, as she noted in her resignation letter.  There were no problems with that on her watch.  And unlike some Trump appointees, she was scandal-free, and perhaps those general ethical qualities are why she never exceeded the bounds of her authority as homeland security secretary.

Yet she made little progress on the border crisis.  You could see the strain on her face in her photos.  Was that her fault?  Not really.  She was demonized constantly by the left-wing press, she had to deal with leftist lawsuits over simple enforcement of the law at every turn, she got nothing but non-cooperation from America's sanctuary cities and states hell-bent on rewriting the law to their liking, she was up against leftist activist judges intent on nullifying U.S. law, and she was even harassed by leftist lunatics in the streets.  In the middle of all this, Nielsen was capable and dignified. 

So it's baffling that President Trump seems to have edged her out, as the press is reporting, or, just as likely, she couldn't stand it anymore, the mercurial president likely being a tough boss to work for.  In her last photos, she looked tired and sad.  The fact that she tried to defend her record in her resignation letter suggests that the former scenario is more likely.

The New York Times certainly tried to drive the knife in as she made her exit, claiming she was all in for the separation of families at the border, fantasizing that this is something she liked, which, contrary to that beclowning imagining, she said she didn't.  The Times didn't lay any blame for the problem at the feet of illegals, who've clearly been using their children as foils for easy entry into the U.S., placing them in cartel human-smuggling hands on dangerous desert journeys through outlaw badlands in a bid to make it to the front of the queue ahead of the others trying to get in.

It's nonsense.  Nielsen wasn't what the Times tried to paint her as, and the Times' pants-wetting about her successor being "worse" is also likely nonsense.  The next secretary of homeland security is going to have just as many problems getting results as Nielsen did, based on all those external factors described.

The only thing Nielsen lacked was image.  She was a hesitant public speaker with a girlish voice.  She sometimes had a tin ear for dressing (on a border visit, she once wore a little old lady winter coat with a brooch).  And, yes, this is cruel, but she's a very pretty woman, with a short, petite stature and bright blonde hair, which has ways of working against her authority on the image front.  It was just image; it was not her substance.  Sadly, image might have been her only problem.  President Trump is savvy about such things, but it's sad to see her exit for something that could have been as unfair as that.  Seriously, she did the best job possible with what she was handed. 

If the next guy can do better than that (and without stumbling on something she didn't), he will be pulling off a miracle.

As for Nielsen, one can only hope her next landing pad will be just as fitting for her talents.