At a time the American presidency is engulfed in domestic and foreign policy crises requiring the attentions of our best experts in both realms, we continue to be led by a crude and unschooled carnival barker who has populated the bureaucracy with know-nothings and adoring cronies.

His first year-plus in the Oval Office has been marked by a game of musical chairs in which original appointments have been scrapped and replaced by loyalists committed to letting Donald Trump be himself, no matter how disruptive or ill-informed he may be of the norms of governance in our small-d democracy.

The latest glaring example is his selection of his personal White House physician, Ronny L. Jackson, a career Navy doctor with no managerial experience, to head the Veterans Administration, the second-largest federal bureaucracy of 377,000 employees running more than 1,200 medical facilities.

Dr. Jackson is to replace David Shulkin, who doomed his own tenure with mindless extravagance, according to the VA inspector general, of spending more than $122,000 of taxpayer money on travel for himself and his wife. Dr. Jackson first drew public attention in declaring our overweight president fit as a fiddle at 239 pounds, bordering on the definition of obesity.

More generally disturbing among veteran presidential watchers here have been the recent appointments of Secretary of State Mike Pompeo (replacing Rex Tillerson) and White House National Security Adviser John Bolton (replacing H.R. McMaster). This pair of war hawks, who in critics’ eyes form President Trump’s war cabinet, comes amid talk and fear of prospective U.S. military actions in North Korea and Iran.

Overall, the specter of Mr. Trump cleaning house of individuals on the White House staff and in the broader bureaucracy not sufficiently in tune with his politics, or even his personal quirks, has already resulted in reducing the image of the presidency to a cartoon-like punching bag.

President Trump’s clinging reputation as a serial denier of past womanizing has been reinforced recently by two widely televised accusations by women, one of them a porn film actress charging she was paid $130,000 in hush money by a Trump lawyer just before his 2016 election.

The allegations of presidential sexual dalliances are hardly new, going back at least to Grover Cleveland in the 1884 election, taunted by cries of “Ma! Ma! Where’s My Pa!” referring to an alleged out-of-wedlock child. More recently, Bill Clinton was impeached but acquitted by Democratic senators holding their noses to save him in 1999 during the Monica Lewinsky scandal.

But the Trump presidency has been one disruption of one sort or another from the outset, whether from his own alleged personal antics and comments or the chaos that his leadership style has wrought from the outset.

Hanging over it all remains the U.S. intelligence community’s unanimous finding of Russian meddling in the 2016 American presidential election and Special Counsel Robert Mueller’s investigation of possible Trump campaign collusion, denied by him but seemingly moving inexorably toward possible complicity and ultimate impeachment. President Trump has said not a word about what he intends to do to defend his country against this outrageous attack on the heart of our political system.

Seldom, if ever, has an American president been so plagued by an aura of incompetence combined with allegations of personal instability as Donald Trump is today, as he strives to shake up the machinery and personnel of his national administration in only the start of its second year.

The last two presidents somewhat similarly embattled, the late Richard Nixon and Bill Clinton, had at least strong public images of competence in running the government. Nixon was generally regarded as well-schooled in the affairs of Washington and the world beyond, until his own internal corruption undid him in the Watergate self-immolation in 1972-74. And Mr. Clinton survived his lying about the Lewinsky affair, beat the impeachment rap in 1995, and went on to a largely successful second presidential term as a canny and effective political operative.

As for President Trump, the jury of public opinion is still out as he clings to a core of less than 40 percent in the polls of enthusiastic supporters. They continue to swallow his snake-oil elixirs as he makes up governing the country as he goes along, brazenly insisting he is making America great again.

Jules Witcover is a syndicated columnist and former longtime writer for The Baltimore Sun. His latest book is “The American Vice Presidency: From Irrelevance to Power” (Smithsonian Books). His email is juleswitcover@comcast.net.