WASHINGTON (NYTIMES) - It was one thing in 2016 for top Republicans to take a stand against Mr Donald Trump for president: He wasn't likely to win anyway, the thinking went, and there was no ongoing conservative governing agenda that would be endangered.

The 2020 campaign is different: Opposing the sitting president of your own party means putting policy priorities at risk, in this case appointing conservative judges, sustaining business-friendly regulations and cutting taxes - as well as incurring the volcanic wrath of Mr Trump.

But, far sooner than they expected, growing numbers of prominent Republicans are debating how far to go in revealing that they won't back his reelection - or might even vote for Mr Joe Biden, the presumptive Democratic nominee. They're feeling a fresh urgency because of Mr Trump's incendiary response to the protests of police brutality, atop his mishandling of the coronavirus pandemic, according to people who spoke on the condition of anonymity to disclose private discussions.

Former President George W. Bush won't support the reelection of Mr Trump, and Mr Jeb Bush isn't sure how he'll vote, say people familiar with their thinking. Senator Mitt Romney of Utah won't back Mr Trump and is deliberating whether to again write in his wife, Ann, or cast another ballot this November. And Mrs Cindy McCain, the widow of Senator John McCain, is almost certain to support Mr Biden but is unsure how public to be about it because one of her sons is eyeing a run for office.

None of them voted for Mr Trump in 2016, but the reproach of big Republican names carries a different weight when an incumbent president and his shared agenda with Senate leaders are on the line.

Former Republican leaders like the former Speakers Paul Ryan and John Boehner won't say how they will vote, and some Republicans who are already disinclined to support Mr Trump are weighing whether to go beyond backing a third-party contender to openly endorse Mr Biden. Retired military leaders, who have guarded their private political views, are increasingly voicing their unease about the president's leadership but are unsure whether to embrace his opponent.

Mr Biden himself, while eager to win support across party lines, intends to roll out his "Republicans for Biden" coalition later in the campaign, after fully consolidating his own party, according to Democrats familiar with the campaign's planning.

ACCELERATING OPPOSITION

The public expressions of opposition to Mr Trump from parts of the Republican and military establishment have accelerated in recent days over his repeated calls for protesters to be physically constrained, "dominated," as he put it, and his administration's order to forcefully clear the streets outside the White House so he could walk out for a photo opportunity. His conduct has convinced some leaders that they can no longer remain silent.

Former Defence Secretary Jim Mattis' blistering criticism of Mr Trump and the admission this past week by Senator Lisa Murkowski of Alaska that she is "struggling" with whether to vote for the sitting president of her own party have intensified the soul-searching taking place, forcing a number of officials to reckon with an act that they have long avoided: stating out loud that Mr Trump is unfit for office.

"This fall, it's time for new leadership in this country - Republican, Democrat or independent," said William H. McRaven, the retired Navy admiral who directed the raid that killed Osama bin Laden. "President Trump has shown he doesn't have the qualities necessary to be a good commander in chief."

Mr McRaven, in an interview on the 76th anniversary of D-Day, noted that those wartime leaders inspired Americans with "their words, their actions and their humanity". In contrast, he said, Mr Trump has failed his leadership test.

"As we have struggled with the Covid pandemic and horrible acts of racism and injustice, this president has shown none of those qualities," Mr McRaven said. "The country needs to move forward without him at the helm."

Mr Trump won election in 2016, of course, despite a parade of Republicans and retired military officers who refused to support him. Far more current GOP elected officials are publicly backing Mr Trump than did four years ago.

Among his unwavering supporters are Republican leaders like Mr Mitch McConnell, the Senate majority leader, and past foes like Senators Ted Cruz and Lindsey Graham. And polls today indicate that rank-and-file Republicans are squarely behind the president, although that is in part because some Republicans who can't abide Mr Trump now align with independents.

Yet it would be a sharp rebuke for former Trump administration officials and well-known Republicans to buck their own standard-bearer. Individually, they may not sway many votes - particularly at a time of deep polarisation. But their collective opposition, or even resounding silence, could offer something of a permission structure for Trump-skeptical Republicans to put party loyalty aside.

Mr John Kelly, Trump's former chief of staff and a retired Marine general, would not say who he would vote for, though he did allow that he wished "we had some additional choices."

Mr Dan Coats, a former Republican senator who was Trump's director of national intelligence, "has been concerned about the negative effect on the intelligence community by the turmoil of turnover at DNI," said Mr Kevin Kellems, a longtime adviser to Mr Coats, adding that the former spy chief is "encouraged by the confirmation of a new DNI and career intelligence deputy". As for who Mr Coats will vote for, "ultimately he remains a loyal Republican but he believes the American people will decide on Nov 3," Mr Kellems said.

Mr Joseph Maguire, a retired three-star admiral who served as Trump's acting intelligence chief, invoked the comments of Mr Mattis and two former chairmen of the Joint Chiefs of Staff who also criticised the president this past week.

"Jim Mattis, Mike Mullen and Marty Dempsey are all good friends, and I respect them tremendously," Mr Maguire said. "I am in alignment with their views." Asked who Mr Boehner and Mr Ryan will vote for in November, representatives to both former House speakers declined to say.

Mr Colin Powell and Ms Condoleezza Rice, who both served as secretary of state under Bush, have also so far declined to state their intentions.

'DRIVING US CRAZY'

A number of current GOP lawmakers and governors are also wrestling with what to do - and what to say - as they balance conscience, ideology and the risk to themselves and their constituents that comes from confronting Trump.

Representative Francis Rooney of Florida has donated millions of dollars to Republican candidates over the years, served as Mr Bush's ambassador to the Vatican and hasn't voted for a Democrat in decades.

But Mr Rooney said he is considering supporting Mr Biden in part because Mr Trump is "driving us all crazy" and his handling of the virus led to a death toll that "didn't have to happen". Mr Rooney is not seeking reelection, so he is not worried about future electoral prospects. He said his hesitation with Mr Biden owes to uncertainty about whether left-wing Democrats would pull the former vice-president out of the political mainstream.

"What he's always been is not scary," Mr Rooney said. "A lot of people that voted for President Trump did so because they did not like Hillary Clinton. I don't see that happening with Joe Biden - how can you not like Joe Biden?"

Mr Rooney has been gently lobbied by one of Mr Biden's closest allies in Congress: Senator Chris Coons of Delaware, who has effectively become the former vice-president's emissary to current and recent Republican lawmakers.

Among the anti-Trump Republicans now out of office, recent events have only vindicated their sense of alarm - and nudged them toward embracing Mr Biden.

"For people who were long waiting for that pivot, the last week has shown, if anything, he's dug in and not even making an attempt to appeal to anybody outside his hard base," said former Senator Jeff Flake of Arizona, who is close to Coons and in conversation with him about how and when to formalise his support for Mr Biden.

Former Representative Mark Sanford, who briefly challenged the president in the Republican primary, said last year that he'd support the president if he won the nomination.

But now Mr Sanford believes Mr Trump is threatening the stability of the country.

"He's treading on very thin ice," said Mr Sanford, also a former South Carolina governor, who is engaged in frequent conversations with other Republicans about how to proceed.

There are already a number of Republican groups dedicated to defeating to Mr Trump, and former lawmakers, strategists and policymakers who are plotting what and when to say about the election.

"There is an organised effort about how to make our voices useful in 2020," said Ms Kori Schake, who worked at the National Security Council and State Department under Bush and was an editor with Mr Mattis of the book "Warriors and Citizens," about the civil-military divide.

She said a number of officials who worked for both Presidents Bush and Ronald Reagan, many of whom signed a 2016 letter opposing Mr Trump, were on Zoom chats and group emails trying to determine how to express their opposition and whether it should come with an endorsement for Mr Biden. The effort to gather more anti-Trump Republicans to speak out is being spearheaded by Mr John B. Bellinger III, who also worked in Mr Bush's NSC and State Department.

Some Republicans believe Mr Mattis made their task easier.

"It laid the cornerstone of fighting back against Trump," said former Senator John W. Warner of Virginia, who noted that as Navy secretary he once served as "boss" to Mr Mattis, then a youthful Marine officer.

"He said: 'I can judge the man.'"