Donald Trump is the first US president in decades who does not even pretend to unite the American people, his former secretary of defence said in a blistering attack.
Jim Mattis, a respected former US Marine Corps general, has kept quiet about his time in the White House with Mr Trump since he walked out a year and a half ago.
But as a growing number of high-profile figures, serving and former, make their position known amid a surge in national anger at the killing of George Floyd in police custody, Mr Mattis also broke his silence.
“Donald Trump is the first president in my lifetime who does not try to unite the American people, does not even pretend to try," he said.
"Instead, he tries to divide us. We are witnessing the consequences of three years of this deliberate effort.
"We are witnessing the consequences of three years without mature leadership."
Over the past four years, a consensus has grown around those who deal with Mr Trump.
They say flattery, praise and a quiet word yield results while public condemnation of the White House earns a quick rebuke from his Twitter account.
“Probably the only thing Barack Obama and I have in common is that we both had the honour of firing Jim Mattis, the world’s most overrated general,” the president tweeted in response to Mr Mattis's open letter.
Protests, president and national direction in their own words
The US is at an important junction. In less than six months, Americans will head to the polls in one of the most polarised elections in a generation, between Mr Trump and former vice president Joe Biden.
America today is more divided than on the eve of the 2016 election that brought Mr Trump to power, Timothy Kneeland, chair of history and political science at Nazareth College in Rochester, told The National.
Although the mass protests that have broken out over the killing of Floyd in Minneapolis last week were unexpected, the battle lines for November are being quickly laid out.
Mr Kneeland said that despite the president appearing to be under immense pressure, even spending a night in a bunker as fires burned outside a darkened White House, “he is happiest when there is chaos".
Mr Trump is using a strategy “straight from Richard Nixon's playbook” in the narrow 1968 victory, Mr Kneeland said.
“He truly believes that his law and order message will resonate with white voters, who still outnumber people of colour in the US.”
But Mr Kneeland said Mr Mattis’s comments, and those this week from former presidents Barack Obama and George Bush and others, will have a political impact.
Peter Yacobucci, associate professor at SUNY Buffalo State College, said figures such as Mr Mattis were not the president’s traditional adversaries, so their statements carried significant influence.
“[Mr Mattis] is beloved within the military and for him to make such a clear denouncement of the president will have an impact on current and former military who, by-and-large, have stood with the president,” Mr Yacobucci said.
He said Mr Trump looking to sent in the military and the national guard to police the streets is “diametrically opposed to what the large majority of our all-volunteer service members signed up for".
Therefore, it could undermine one of his most loyal support bases.
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Mr Kneeland said the impact would also be felt in the Senate and the Congress.
“Senate leaders, already anxious about losing the Senate to the Democrats, are more concerned about the impact of his statement in states where Democrats are leading in statewide polls,” Mr Kneeland said.
Nationally, Mr Biden has opened a nearly 10-point lead in some polls and the mood also plays into the local, state, congressional and Senate races also open this year.
But polling data and uneasy congresspeople are unlikely to alter the president’s course.
“His actions suggest his natural instincts are to double down on his most aggressive combative nature," Mr Yacobucci said.
"Recent polling, especially those done since the George Floyd murder surfaced, suggest this is driving many away from the president."
But as Mr Kneeland points out, since 2016 Mr Trump has reformed the Republican party.
Gone are many of those who saw him as the antithesis of their conservative values and in their place are firebrand ideologues ready to back his every word.
While even the president's current secretary of defence, Mark Esper, risked his job to say he did not agree that the protests were a sufficient threat to warrant the military, Arkansas Senator Tom Cotton took to The New York Times to call for the intervention.
“One thing above all else will restore order to our streets: an overwhelming show of force to disperse, detain and ultimately deter lawbreakers,” Mr Cotton wrote.
But there is a sign that some more centrist Republicans are mobilising against Mr Trump.
On Monday, a new political action group called 43 Alumni For Biden was established by former officials in Mr Bush's administration to gather donations to Mr Biden's campaign.
Neither Mr Kneeland nor Mr Yacobucci regard November’s elections as a salve to the nation’s divisions.
“It will take a remarkable leader that simply may not be currently present,” Mr Yacobucci said.
Mr Kneeland sees it as a long, drawn-out process.
“The only thing that may change any of this is for the younger generation to embrace a new politics and wait for the older generation of voters to age out of the political process,” he said.
- Additional reporting by Cody Combs