Donald Trump's former advisers have an obligation to warn American voters that the former president is dangerously unfit to serve another term in office.

Although virtually all House and Senate Republicans have fallen in line behind his re-election campaign, and GOP primary voters so far have made him the presumptive nominee, Washington Post columnist Jennifer Rubin noted that high-level advisers who served alongside him have overwhelmingly refused to endorse him for a second term.

"This unprecedented rebuff, from everyone from former vice President Mike Pence to former defense secretary Mark T. Esper to former attorney general William P. Barr to former chief of staff John F. Kelly, speaks to Trump’s manifest flaws and how they are visible to those who know him best," Rubin wrote. "Even more stunning, these former advisers have shared hair-raising observations of Trump’s outbursts, mind-set and personal depravity."

Kelly recalls the former president favorably commenting on Adolf Hitler doing "some good things" and generally admiring dictators, while Esper has revealed that Trump wanted to deploy active-duty troops in Washington, D.C., and suggested shooting protesters with whom he disagreed, and Barr has described him as reckless, a narcissist and a "troubled man."

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"Though these Republicans regrettably have not had the wherewithal to endorse President Biden, the only candidate capable of preventing the manifestly unfit former president from returning to power," Rubin wrote, "they can still serve their country by preventing their old boss from regaining power — power, this time, without the guardrails they provided in his first term."

Just as mental health professionals have a duty to warn authorities or a potential victim if one of their patients appears to pose a threat to others, those who have taken an oath of office also have the same obligation to warn the country of the threat Trump poses to national security and democratic institutions.

"Their observations, not well known to most voters, would be powerful and frightening because they go to the heart of his capacity to govern in a democracy," Rubin wrote.

"Trump no doubt will continue to rage against his former advisers, despite his boast that he hired only the 'best people,'" she added. "But a unified and consistent effort from a substantial number of former high-ranking officials to educate the American people, especially 'soft' Republicans who continue to hold these former Trump aides in high esteem, could act as a powerful counterweight to the false equivalence that afflicts too much campaign coverage."