The president will be absent for McCain’s memorial services – a clear sign of his failure to accept the responsibilities of a head of state

“The lion of the US Senate,” said Barack Obama during a stirring eulogy at the funeral mass for Senator Ted Kennedy in 2009. Listening at the Basilica of Our Lady of Perpetual Help in Boston were George W Bush, Jimmy Carter, Bill and Hillary Clinton and Senator John McCain.

Death came to McCain nine years to the day after Kennedy, and by the same cause: brain cancer. Tributes are being paid this week, including a memorial service at the National Cathedral on Saturday where Washington high society will gather. This time, however, the president will be nowhere to be seen.

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Donald Trump’s absence – perhaps at the White House, maybe even on the golf course – will not only underscore the antipathy between him and McCain, who made clear he did not want Trump at his funeral. It is also a sign of how the celebrity businessman has embraced the power of the presidency but shunned the responsibilities of a head of state.

Last Saturday, Trump gave a grudging response to McCain’s death. Past presidents, senators and various organisations unfurled lyrical tributes. Trump resorted to Twitter to offer his “deepest sympathies and respect” to McCain’s family. He added, complete with jarring exclamation mark: “Our hearts and prayers are with you!”

Play Video 1:57 Five times Donald Trump refused to pay tribute to John McCain - video

According to the Washington Post, which dubbed Trump “president non grata”, White House aides had written a statement that honoured McCain’s service as a prisoner of war in Vietnam and his long career on Capitol Hill and described him as a “hero” – only for Trump to veto it in favour of the 21-word tweet.

Then came a flag farce. The stars and stripes flew at half-mast at the White House, as is protocol, yet on Monday morning it was back at full mast, prompting widespread criticism – especially as flags remained lowered on other federal buildings. Gen Michael Hayden, former director of the CIA, tweeted a photo of the flag flying high above the executive mansion with the comment: “Remember this image the next time this president talks about disrespecting veterans.”

By afternoon the blunder had been corrected. Trump, who seldom backs down, issued a statement that began with a negative: “Despite our differences on policy and politics, I respect Senator John McCain’s service to our country and, in his honor, have signed a proclamation to fly the flag of the United States at half-staff until the day of his interment.”

McCain is a national hero in the national cathedral and Trump will be sitting fuming in the White House Sally Quinn

But the damage had been done. Former president Jimmy Carter told Fox News Trump “made a mistake” with the tweet that made no mention of McCain’s military and political service, adding on the MSNBC that the subsequent official statement was “still not as enthusiastic as it should be”.

Trump acknowledged McCain in public remarks that night. But he will play no part in the senator’s lying in state in the US Capitol rotunda on Friday, where Vice-President Mike Pence will deliver remarks and present a wreath; nor at the national memorial service on Saturday where Bush, Obama and former secretary of state Henry Kissinger will be among those delivering tributes; nor at his burial at the US Naval Academy in Annapolis on Sunday, where Senator Lindsey Graham and Gen David Petraeus will speak.

Once again, Trump has defied the conventions of the capital and found himself an outcast.

Sally Quinn, an author, contributor to the Washington Post and celebrated Washington host, said: “He has absolutely no respect for any kind of tradition in Washington. It is such bad form.

Facebook Twitter Pinterest John McCain’s casket is carried out of the North Phoenix Baptist church on Thursday. Photograph: Conor Ralph/Reuters

“There is now this level where nothing he does is shocking any more. All week people have been saying can you believe the flag was up and then down and then up again, but then there’s a shrug. That’s who he is. He’s a man without honour.”

In April, there was a glaringly obvious, Trump-shaped hole at former first lady Barbara Bush’s funeral in Houston, where his wife Melania Trump was photographed alongside past presidents and first ladies, looking curiously happy.

Quinn commented: “This is going to be much worse. McCain is a national hero in the national cathedral and Trump will be sitting fuming in the White House. Saturday is going to be a very bad day for Donald Trump.”

Larry Jacobs, director of the Center for the Study of Politics and Governance at the University of Minnesota, suggested Trump has failed to understand the ceremonial power of the presidency to bring people together and promote his own causes.

“Sure,” he said, “the guy is coarse, but that’s not the main issue here. The flag going up and down is a metaphor for his lack of realpolitik qualifications. Machiavelli would be blushing at the sheer ineptitude.”

Saturday will be a moment of “national humiliation”, Jacobs said. “It’s part of a big pattern. In so many ways, Donald Trump has marooned himself on a faraway island. His boat is now wrecked on the shore and he’s sitting sulking.”

Along with the Bush funeral, Trump was not invited to the wedding of Prince Harry and American actor Meghan Markle.

Sidney Blumenthal, a former assistant and senior adviser to Bill Clinton and biographer of Abraham Lincoln, said: “He’s a designated non-mourner. From Windsor to Washington, he is beyond the pale. I can’t think of another president who is beyond the pale.”

In Washington itself, the president remains something of a pariah, apparently dining only at the White House or his nearby luxury hotel.

“He lives in his own little kingdom, his own kleptocratic state which has the physical manifestation of his hotel, which should have a moat around it,” Blumenthal said. “He just doesn’t mix at all.”