It’s the standard Washington protocol — a member of Congress dies, and the flags over official buildings are flown at half-staff. That’s what happened when John McCain died Saturday.

But first thing Monday morning, the flag over the White House was back at full-staff, and a barrage of bitter criticism soon followed, with detractors — including the American Legion — interpreting the fleeting tribute as a sign of President Trump’s pettiness.

He had refused to utter McCain’s name earlier this month when signing the defense policy bill named for the senator. He had rejected staff suggestions over the weekend that he issue a statement upon McCain’s death. And now he was refusing to follow a tradition of leaving the flag at half-staff until interment.

Then, suddenly, the flag was back at half-staff Monday afternoon, and the president issued a statement offering “respect” for McCain.

The White House flag was back at half-staff Aug. 27, after it was raised to full-staff. It was lowered over the weekend following the death of Sen. John McCain. (Reuters)

By day’s end, it had become clear that in his stubborn defiance of protocol, the president had single-handedly turned the death of McCain into yet another political firestorm that was all about Trump.

“It’s all a self-inflicted wound, especially the flag,” said Ari Fleischer, who worked as White House press secretary under President George W. Bush. “The ceremonial things, the traditional things that keep a lot of people together — even if you have policy or personal disagreements, you have to know where to draw that line.”

Trump, Fleisher added, “too often draws that line in a way that hurts himself because he thinks he is hurting others.”

During an Oval Office meeting with Kenyan President Uhuru Kenyatta, President Trump ignored reporters' questions about Sen. John McCain (R-Ariz.). (The Washington Post)

The day’s events were punctuated by a letter read aloud by McCain’s longtime adviser in which the Arizona Republican obliquely rebuked Trump posthumously.

Trump is not expected to attend the funeral or memorial services in Washington for McCain, a senior White House official said. Vice President Pence will speak at a ceremony Friday at the U.S. Capitol Rotunda. Chief of Staff John F. Kelly, Defense Secretary Jim Mattis and national security adviser John Bolton will represent the administration at McCain’s private funeral on Sunday at the U.S. Naval Academy in Annapolis.

In his statement Monday, Trump wrote: “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.”

After McCain’s death on Saturday at the age of 81, Trump had initially offered words of condolence to the senator’s family in a tweet that made no mention of McCain’s storied service in the military and on Capitol Hill — a stark contrast with the effusive praise for McCain voiced by lawmakers, world leaders and members of the military.

That was followed by nearly two full days of silence from the president, who ignored almost a dozen shouted questions about McCain from reporters at three separate White House events on Monday while he tweeted on a wide range of other topics, from Tiger Woods to trade with Mexico.

Trump’s silence reflected the bitter years-long battle between the two men. Trump has said that McCain, who spent more than five years as a POW in Vietnam, was “not a war hero” and continued to snub the longtime senator throughout his battle with brain cancer.

McCain, in turn, pulled no punches in criticizing the president on foreign policy and other issues, most recently in a stinging denunciation of Trump’s summit with Russian President Vladi­mir Putin in Helsinki last month.

The Washington Post reported Sunday that Trump had rejected the advice of top aides who advocated releasing an official statement that gave the decorated Vietnam War POW plaudits for his military and Senate service and called him a “hero.”

On Monday morning, images of the flag atop the White House at full-staff — and behind it, the Washington Monument encircled by flags, all at half-staff — blazed across the nation’s TV and computer screens. Criticism was not far behind.

The American Legion, a veterans organization, issued a sternly worded statement calling on Trump to treat McCain with more reverence.

“On the behalf of The American Legion’s two million wartime veterans, I strongly urge you to make an appropriate presidential proclamation noting Senator McCain’s death and legacy of service to our nation, and that our nation’s flag be half-staffed through his [interment],” said Denise Rohan, the group’s national commander.

Several administration officials said Trump was frustrated with the TV coverage and felt besieged — that nothing he said about McCain would be enough. Trump also suggested to advisers that many of those speaking out on television were merely looking for reasons to attack him and that some of the same people now praising McCain previously did not like the senator.

Yet among those hailing McCain was Ivanka Trump, Trump’s daughter and senior White House adviser, who on Monday called the late senator “an American patriot who served our country with distinction for more than six decades.”

“The nation is united in its grief and the world mourns the loss of a true hero and a great statesman,” the first daughter said in remarks at a meeting of the Organization of American States in Washington.

Trump told advisers over the weekend that lavishing praise on McCain would not be genuine because he did not feel that way. “Everyone knows we don’t like each other,” the president said, according to one White House official who spoke with him.

Even so, after speaking with a number of close advisers Monday, including Bolton, Mattis, Secretary of State Mike Pompeo and White House press secretary Sarah Huckabee Sanders — all of whom urged him to clean up the mess — the president backtracked.

Trump wrote much of Monday’s statement, White House officials said, and wanted to express that he disagreed with McCain on policy and politics.

Later, at a White House dinner celebrating evangelical leaders, Trump said that “our hearts and prayers” are with McCain’s family and made note of this week’s planned events in honor of the senator.

“We very much appreciate everything that Senator McCain has done for our country,” Trump said.

Trump’s proclamation came hours after an emotional news conference in Phoenix at which McCain’s longtime adviser and family spokesman, Rick Davis, read a farewell statement from the senator that contained a veiled critique of the president. In the letter, McCain did not name Trump but called on Americans to rally behind the country’s founding principles rather than hiding behind walls and succumbing to political tribalism.

“We weaken our greatness when we confuse our patriotism with tribal rivalries that have sown resentment and hatred and violence in all the corners of the globe,” McCain wrote in the letter. “We weaken it when we hide behind walls, rather than tear them down, when we doubt the power of our ideals, rather than trust them to be the great force for change they have always been.”

Trump campaigned on a promise to build a wall across the U.S. border with Mexico and force Mexico to pay for it.

McCain’s statement also referred at some length to the populist and protectionist forces that helped propel Trump to the office McCain twice failed to win.

“We are citizens of the world’s greatest republic, a nation of ideals, not blood and soil,” McCain wrote. “We are blessed and are a blessing to humanity when we uphold and advance those ideals at home and in the world.”

White supremacists who marched in Charlottesville last year chanted “blood and soil,” a translation of a Nazi slogan. Trump appeared to defend the rallygoers, who clashed with counterprotesters, when he said there were “fine people on both sides.”

At the Capitol on Monday, the Senate convened for the first time since McCain’s death. Inside the chamber, the wooden desk that McCain occupied for six terms was draped in black. A vase of white flowers had been placed on top.

One by one, McCain’s colleagues rose to deliver somber tributes to him. They included Sen. Jeff Flake (R), McCain’s junior Arizona colleague, who welled with emotion as he spoke of the late senator’s legacy.

“If John McCain can forgive the North Vietnamese torturers, we can at least forgive each other,” Flake said.

Yet it was Trump’s actions that dominated the conversations between senators and reporters in the marble hallways just outside the chamber.

“I don’t know why the administration had the flag lowered for such a brief period of time,” Sen. Susan Collins (R-Maine) said. “It seems to me that it would be appropriate to keep the flag at half-mast until Senator McCain has been buried.”

Asked whether Trump had let his personal views stand in the way of paying proper respects to McCain, Collins responded: “It certainly looks that way.”

Some Trump allies, including Sen. James M. Inhofe (R-Okla.), suggested the dust-up was being blown out of proportion. Both Trump and McCain were “two of the most stubborn people I ever met,” Inhofe said, arguing that if McCain had been the one in the White House, he would have behaved similarly to Trump.

“If the tables were turned, it’d be the same way with McCain. The flag is lowered, so he’s doing it with respect, but everyone knows they didn’t get along,” Inhofe said.

Other lawmakers decided to sidestep the topic entirely.

“I’m not gonna get into that,” Sen. Cory Gardner (R-Colo.) said when asked about Trump’s re-lowering of the flag. “What I am gonna say is this week’s about John McCain and his legacy and his lifetime of service to this country. You can get into the fight between the president and John McCain. I’m not going to.”

The varied opinions on Capitol Hill were themselves emblematic of the America comprising “three-hundred-and-twenty-five million opinionated, vociferous individuals” that McCain described in his letter. In the end, the Arizona Republican noted, “we have always had so much more in common with each other than in disagreement.”

“If only we remember that and give each other the benefit of the presumption that we all love our country, we will get through these challenging times,” he wrote. “We will come through them stronger than before. We always do.”

Anne Gearan, Gabriel Pogrund and Avi Selk contributed to this report.