The public learned on March 10, 2015 that Hillary Clinton had more than 60,000 emails on her private email system, and that she had turned over "about half" of them to the State Department and destroyed the rest, which she said were "personal" and "not in any way related" to her work as Secretary of State.

The public learned later the lengths to which Clinton went to make sure the "personal" emails were completely and permanently deleted. Her team used a commercial-strength program called BleachBit to erase all traces of the emails, and they used hammers to physically destroy mobile devices that might have had the emails on them. The person who did the actual deleting later cited legal privileges and the Fifth Amendment to avoid talking to the FBI and Congress.

Clinton's lawyer, David Kendall, told Rep. Trey Gowdy, chairman of the House Benghazi Committee, that investigators could forget about finding any of those emails, whether on a device or a server or anywhere. Sorry, Trey, he said; they're all gone.

It was, as the New York Times' Mark Landler said in August 2016, the "original sin" of the Clinton email affair — that Clinton herself, and no independent body, unilaterally decided which emails she would hand over to the State Department and which she would delete.

Still, there were people who did not believe that Clinton's deleted emails, all 30,000-plus of them, were truly gone. What is ever truly gone on the Internet? And what if Clinton were not telling the truth? What if she deleted emails covering more than just personal matters? In that event, recovering the emails would have rocked the 2016 presidential campaign.

So, if there were an enormous trove of information potentially harmful to a presidential candidate just sitting out there — what opposing campaign wouldn't want to find it?

There have been recent reports that last summer a Republican named Peter W. Smith made some sort of effort to find the missing Clinton emails, apparently getting in touch with hackers, some of whom may have been Russian. But nothing came of it, and no evidence has emerged that Smith was connected to the Trump campaign. (The 81-year-old Smith later committed suicide, apparently distraught over failing health.)

In a phone conversation Friday, Corey Lewandowski, the Trump campaign manager who was fired on June 20, 2016, said he never heard of or communicated with Smith, and wasn't aware of any effort to find the missing Clinton emails. "I never solicited, or asked anybody to solicit or find a way to get these potential emails," Lewandowski said. "And to the best of my knowledge, nobody [in the campaign] did either."

Still, Lewandowski added that, "In the world of cybersecurity, it's fairly well known that when you delete emails, they're not gone."

Another former top Trump aide said that was a common view in the campaign. "The feeling was that they [the emails] must exist somewhere," the former aide said, "because once something is digital, it's never truly gone."

"Trump believes that," the aide added.

Still, the aide also said he had never heard of Peter W. Smith, and didn't know of any effort to find the emails. "There was never a thought of who might have them," the aide said. "Nobody at the campaign was trying to find them."

Both Lewandowski and the other former aide stressed the greatest political value of the missing emails, as far as Trump was concerned, was that they gave Trump a way to "poke" and "troll" his Democratic opponent. The Clinton team was BleachBitting and swinging hammers to smash devices — and she says everything was on the up and up, that she has nothing to hide? Candidate Trump could riff on that all day. It was as if Clinton were trying her best to look guilty, to Trump's political benefit.

But at least one high-ranking Trump team member apparently did believe the missing Clinton emails still existed. In August 2016, Gen. Michael Flynn, then the Trump campaign's top national security adviser, discussed the emails with a conservative radio host named John B. Wells. "The big question is, does somebody have more emails?" Flynn began:

Does somebody have the 30,000? The likelihood of that ... the likelihood somebody has all of those emails, at a nation-state level, meaning Russia, China, Iran, North Korea, or even other countries, or some other large hacktivist group, like the WikiLeaks group that we know exists — the likelihood is very high, and I'm talking like better than 95 percent. I would actually bet a paycheck on it, that somebody has it.

Flynn, of course, was a former director of the Defense Intelligence Agency, so he should know something about that. Flynn also had Trump's ear on national security and other matters. And he was saying the emails are out there, somewhere.

Which leads to a question. Would it have been appropriate for the Trump campaign to try to find the emails? After all, the emails were under congressional subpoena, under FBI investigation, of intense public interest, and a potentially explosive issue in the presidential campaign. What opposing campaign wouldn't want to know what was in them?

Look at a few possible scenarios. What if a member of the Clinton team defected and offered them to the Trump campaign? Would it have been appropriate for Trump to accept?

Or: What if a rogue hacker — "a 400-pound person sitting in bed," as Trump once said — got the emails and offered them to the campaign? Would accepting under those circumstances have been appropriate?

What if an intelligence operative from a friendly country got them and offered them? And what about an unfriendly country?

Would there be a scale, from standard oppo research on one end to treason on the other, depending on how the emails were acquired?

I posed those hypotheticals — at least I think they are hypotheticals — to three veteran Republican operatives: Tim Miller, who served as spokesman for Jeb Bush's 2016 campaign; David Carney, a New Hampshire-based strategist who's been involved in dozens of campaigns; and Barry Bennett, who ran Ben Carson's 2016 campaign and also served briefly as an adviser to the Trump effort.

Miller, a vocal critic of the president, stressed via email the question comes in the context of Russia's hacking of DNC and John Podesta emails. "So I would say that it would be unacceptable in opposition research to do that — hack Podesta/DNC in any situation," Miller said.

"Where Hillary's deleted emails from her time as Secretary of State are concerned, many of those may have actually been public records," Miller continued. "So if they were acquired through a whistleblower or a lucky break scraping Internet archives, that would of course be fair game. That said, under no circumstance would enlisting a hostile government's help be acceptable for a myriad of reasons: legal, ethical, practical (how can you govern when you are in debt to a hostile government)."

For his part, Carney, writing via email, offered ways a campaign might have handled such a situation, had it arisen. "If the emails did show up, most serious campaigns would not touch them directly — legalities and all. But friends of the campaign would strongly encourage the turncoat to dump them to reporters. Easier not to have fingerprints on questionable documents."

"Foreign governments would always use high-level U.S. third parties, not any direct campaign contacts, and most likely they would end up in the media," Carney continued. "So YES — campaigns would seek the emails, but not directly if they were not legally available or the sources were questionable."

Bennett began by noting that the Trump campaign would have had "no ability to find [the missing Clinton emails] all by themselves. There was no tech operation until late summer, and even then it was basic."

"If someone I didn't know reached out and said, 'I have them,' I would have immediately called the committee and said this person says he has them," Bennett continued, via email. "I wouldn't want to touch them. But I would very much want them out there in the public.

"It is still hard for me to believe that copies of them aren't out there somewhere," Bennett added, going on to provide advice for a campaign facing a scandal-plagued opponent.

"Even during the Carson campaign I didn't meet with anyone I didn't know," Bennett said. "How do you know you're not being set up? I had people come to me and say they had dirt on [Ted] Cruz. I passed."

"Information can only be as trusted as the source that gives it to you. You can get easily burned with bad info or even looking like you want dirt. This is why everyone outsources research. No one in their right mind would want to touch documents under subpoena. No lawyer would ever let you."

"All of this being said, of course you want them to go public," Bennett concluded. "If the Russians had them, the last thing they would do is call a goofy record promoter in England and set up a meeting with a lawyer that can't even get a visa. Instead, DHL them from Asia to the New York Times."

Bennett alluded to the odd circumstances of Donald Trump Jr.'s June 9, 2016, meeting with Russians offering some sort of dirt on Hillary Clinton (not, as far as we know, the missing Clinton emails). In the days since the meeting was first reported, several political operatives of both parties have claimed they would never have taken part in such a meeting. While that might indeed be true, some would certainly have tried to find a hands-off way to get damaging material about their opponent into public view.

In the 2016 campaign, everyone knew Clinton had a huge secret — those 30,000-plus "personal" emails — and that she had gone to extraordinary lengths to keep that secret. Many people, and not just partisan warriors, suspected she had something to hide. And now, it should not be a surprise if there were some shenanigans as political operatives tried to learn the real Clinton email story.