To the extent Donald Trump has articulated a coherent foreign policy, it appears a dark shoot-from-the-hip unilateralism that puts him at odds with thinking that has dominated the GOP for generations.
As Trump starts his general election campaign, many Republican foreign policy and national security advisers and thinkers who have spent decades promoting America's preeminent role in world affairs remain deeply skeptical of his views.
They say they are aghast that the GOP nominee boasts of reading little and ignoring expert advice, and instead of gleaning his knowledge of global events from Sunday TV talk shows.
"Donald Trump still has the habits of a reality show host. He says things as dramatically and as provocatively as possible," said Dimitri Simes, president of the Center for the National Interest, a Washington think tank founded by President Nixon.
Trump rang establishment alarms — again — last week when he urged Russia to find Hillary Clinton's deleted State Department emails, apparently daring a foreign adversary to hack a federal agency or a U.S. presidential candidate. (Trump later said he was being sarcastic.)
The episode, along with his fresh criticism of U.S. alliances during the Republican National Convention, cemented doubts for many who still had hopes Trump would tamp down his rhetoric for the fall race against Democratic nominee Hillary Clinton.
"When he entered the race, the overarching concern was lack of experience and an inability or unwillingness to define what his policy would be," said Elliot Abrams, a Middle East expert and military hawk who served as deputy national security adviser to George W. Bush.
"Now, particularly after the convention, he has defined it. And it would destroy the greatest single asset we have, which is our alliance structure," he added.
It was hardly Trump's first break with orthodoxy.
Trump not only has expressed admiration for Russia's authoritarian leader, Vladimir Putin. He has said he might recognize Russia's military annexation of Crimea, which America and its allies consider illegal, and might lift U.S. sanctions imposed on Moscow for its regional aggression.
Trump has challenged the importance of NATO, the transatlantic military alliance born out of World War II, and shaken one of its pillars by saying he might not defend a member nation under attack from Russia or other invaders, as the treaty requires.
He has called for using torture against terrorism suspects, and has said America has no standing to lecture other nations on human rights and the rule of law, as administrations have done since the depths of the Cold War.
He also has suggested upending decades of U.S. efforts aimed at stopping the spread of nuclear weapons by suggesting Japan and South Korea should build their own atomic arsenal rather than rely on the U.S. nuclear umbrella.
By embracing these and other controversial positions, Trump has turned America's postwar political dynamic on its head. Many foreign policy experts now view the Democratic nominee as a more stable hand on national security than the wobbly GOP.
Trump's most ardent supporters see his freewheeling approach as refreshing. They relish his role as a rule breaker who mocks the pious language of diplomats and policy wonks. They agree with his allegation that so-called experts have made America weaker and less respected.
But the response from the GOP foreign policy and national security establishment has been fierce.
Some stalwarts — including Richard Armitage, a former high-ranking Pentagon and State Department official, and Brent Scowcroft, who counseled four Republican presidents — have thrown their support to Clinton.
"It's the fact that our friends aren't going to trust us and our enemies aren't going to fear us" if Trump is elected, said Paul Wolfowitz, a deputy defense secretary under George W. Bush.
Wolfowitz said he has serious concerns about Clinton's foreign policy but will probably vote for her. And he mocked Trump's refusal to release his tax returns, as other presidential candidates have done for decades.
"I wonder how [he would] feel if they leaked his tax returns," he quipped, referring to suspicions that Russia hacked and leaked Democratic Party emails.
The criticism emerged early in the primaries when Trump began rising in the polls.
In February, Robert Kagan, a prominent neo-conservative who argues for American exceptionalism, free-market capitalism and an interventionist foreign policy, called Trump a "Frankenstein's monster," capable of destroying the GOP. He has since backed Clinton.
In March, 121 self-described members of the Republican national security community signed a public letter pledging to work against Trump's election and blasting him as utterly unfit for the White House.
"His vision of American influence and power in the world is wildly inconsistent and unmoored in principle," they wrote. "He swings from isolationism to military adventurism within the space of one sentence."
Eliot A. Cohen, a senior State Department official under President George W. Bush, said he helped draft the letter "so I can look my grandchildren in the eye 15 years from now."
"It's not just demagoguery," Cohen said of Trump's campaign rhetoric. "It's an appeal for a certain kind of dictatorship."
While others won't go that far, at least publicly, they have expressed grave concerns about Trump's lack of specifics on how and when he would use U.S. power.
"Donald Trump, essentially, has simply indicated that he would be tough enough to sock it to him," said Richard Lugar, a former Indiana senator who chaired the foreign relations committee and now leads a think tank devoted to global leadership. "There's not a great deal of analysis [and] almost none at all for the complexities."
Condoleezza Rice, national security adviser and then secretary of State under George W. Bush, declined a request for comment. But someone familiar with her thinking said she has been "disgusted by this whole thing."
Like her, many in the foreign policy elite cut their teeth in the Cold War. They see Trump's apparent camaraderie with Putin, who is steadily reasserting strongman rule in Russia, as naive.
Lanhee Chen, policy director for the 2012 GOP nominee, Mitt Romney, decried what he called Trump's "flippant nature" in addressing foreign policy.
Romney, a former governor of Massachusetts, took time to study and think about foreign policy questions long before he ran for president, Chen said.
"It's a little bit late in the game" to start now, he said. "But the temperament is not something you can study. It's just sort of who you are."
Trump has begun receiving briefings from more knowledgeable policy experts, and now that he is the nominee, will be offered classified intelligence briefings from U.S. officials.
Some conservative policy experts say Trump is being underestimated.
"He appears to have a number of strong instincts that have not yet crystallized into a comprehensive world view," said Paul Saunders, executive director of the Center for the National Interest.
Saunders said wearing his lack of expertise on his sleeve may not impress foreign policy circles, but likely appeals to some voters.
Trump appears unbothered by criticism from people who should be his political allies. His gamble is that voters will disdain "experts" as much as he apparently does.
Those experts, he told a news conference Wednesday in Florida, got the world in the trouble it's in.
"So a lot of the people that you think are good because you know their name or because you see them on television, I don't think are good," he said. "Because look at the end result. The end result is our country is a mess."