“Mr. Kelly has told Mr. Trump it is frustrating for staff members that the president deems most news media stories fake news but believes the ones accusing various advisers of leaking, according to people familiar with the discussions.” (NYT)

Trump
Whether you love or hate Donald Trump, that sentence, buried deep in an article, is a thunderclap.
The President has effectively been outed by his chief of staff over the “fake news” rhetoric and its devastating effect on his staff.
Trump is right that there are leakers as is evidenced by the Kelly quote: someone was willing to talk about Kelly’s interactions with Trump over “fake news.”

John Kelly
General Kelly, as beaten down as he is, is pointing out that selective belief and the presumption of disloyalty can have very damaging consequences.
Kelly, though, is barking up the wrong tree; Trump could care less about staff morale as his vision of loyalty is all one way, top down.
Trump has yet to figure out what many leaders learn quickly–your every utterance matters to someone, most especially if you depend on their loyalty for your success.
Here Trump should be compared to George W. Bush who both showed a measure of restraint and loyalty to his staff, even when they made mistakes.

W
But Trump not only trips on “fake news” he seems to take great delight in publicly torturing staff such as Jeff Sessions, his Attorney General.
As he openly heaps scorn and abuse on Sessions and others he is reminding his staff that they could be next.
Confident and experienced leaders need a “long game” allowing them to back their players even when it pinches.
Abraham Lincoln stood by U.S. Grant despite Grant’s occasional drinking binge and battlefield error, famously saying, “I can’t spare this man; he fights.”

The Young Grant
Eisenhower dealt with George Patton’s outrageous conduct yet kept him in a command position for similar reasons.
It’s ironic that although Trump’s life experience has failed to prepare him for public leadership he has Kelly by his side yet refuses to use him to his potential.
Kelly, a Marine general, knows a thing or two about team building and loyalty to an ideal.
Such are the lessons of history if you care to look.