On Wednesday, Trump’s former defense secretary, Gen. “Mad Dog” Jim Mattis, let himself off the leash. The president’s now-notorious photo op earlier this week, when he ordered police and National Guard troops to brutally disperse peaceful protesters in Lafayette Square outside the White House, was too much for the general to bear.

He criticized Trump with deservedly harsh, direct language. “Donald Trump is the first president in my lifetime who does not try to unite the American people—does not even pretend to try,” Mattis wrote. “We know that we are better than the abuse of executive authority that we witnessed in Lafayette Square. We must reject and hold accountable those in office who would make a mockery of our Constitution.”

Better late than never.

Mattis’s letter could prove a crucial turning point in the upcoming November election. The general is widely respected by prominent Republicans and the party’s rank-and-file. He holds tremendous sway with soldiers, veterans and their families — a crucial voting bloc. But more important, the rebuke from Mattis will signal to other prominent Republicans that the time for private criticism is long past. The time to speak out publicly is now.

During the Trump years, lifelong Republicans split into three camps. In the first camp are the principled conservatives. It is a lonely group, made up of people such as David Frum, Rick Wilson and Bill Kristol, who have established themselves as staunch defenders of anti-Trump conservatism. They have shown no hesitation in making their views known, with some even establishing formidable political advocacy groups working to defeat Trump in November. They will continue to speak out.

The second camp, which comprises most Republicans, is a mix of opportunists and true believers. They have allowed their alleged principles to be swept away in Trump’s takeover of the party. Sen. Lindsey O. Graham (S.C.), who once called Trump a “race-baiting, xenophobic, religious bigot” and a “kook” who was “unfit” for office, is now one of Trump’s most outspoken cheerleaders. Sen. Ted Cruz (Tex.), who endured the humiliation of watching Trump baselessly accuse his father of involvement in the assassination of John F. Kennedy and insult his wife’s appearance, now defends Trump with the blind fealty of a zealot. Senate Majority Leader Mitch McConnell (Ky.) is an amoral Machiavellian, eager to use Trump in any way that advances his agenda.

This camp also includes many Republicans who are genuinely committed to Trump and willingly worship at his altar. No matter what Trump does, this group of opportunists and ideologues will not speak out.

The third group — the quiet disapprovers — is now the one worth watching. Many of these people spoke out against Trump in 2016 but have kept comparatively quiet since. They privately loathe Trump, shaking their heads at his glaring flaws while nodding approvingly at the judges he picks or the tax bills he signs into law.

Mitt Romney is the flagship member of this group. He launched scathing attacks on Trump in 2016 but has moderated his comments since. George W. Bush is clearly in this camp, too, along with his secretaries of state, Condoleezza Rice and Colin Powell. (Both Rice and Powell have criticized Trump, but their more recent criticisms have been tepid.) Mattis used to be in this group but graduated out of it with his scathing (and long overdue) letter.

The quiet disapprovers know that Trump’s failed leadership has compounded three interlocking crises: the pandemic, the ensuing economic collapse and social unrest. They know that right now — when America is seething with anger over racial injustice, a pandemic is killing more people than several wars combined, and the economy is in free fall — it’s a particularly bad time to have a deranged, racist, anti-science president who set up fraudulent businesses and managed to drive casinos to bust. But they don’t say so — at least not without mincing words or making mealy-mouthed appeals to abstract principles in carefully coded language.

They can no longer have it both ways. A second Trump term would be disastrous — for Americans, for U.S. democracy and for America’s standing in the world. The quiet disapprovers agree. They understand the stakes. But unless they speak out when the moment demands it most, they are complicit in that Trumpian devastation.

Moreover, it’s not enough to simply speak out against Trump. Whether you like it or not, we live in a two-party system. If you think Trump is a danger to the country or the Constitution, the only logical course of action is to endorse former vice president Joe Biden. Mattis has broken an important dam that has held back the quiet disapprovers for too long. But it’s not sufficient. Those few remaining prominent Republicans who care about our endangered republic should not just condemn Trump but also endorse Biden. A parade of endorsements from Mattis, Bush, Romney, Rice and Powell could save the country from a second Trump term.

To those quiet disapprovers: Please speak out. If your moral compass isn’t strong enough, act on self-interest. History will judge you. Polls suggest Trump’s ship is sinking. Don’t let your silence tie you to his mast. Don’t let him take us all down with him.

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