The no-longer-presumptive nominees of the Democratic and Republican parties will soon start receiving periodic classified intelligence briefings, with the first one coming perhaps this week. Rarely has this routine ritual received so much public attention - and with good reason.

To anyone who has actually had to protect the nation's secrets, Mrs Hillary Clinton's e-mail set-up as secretary of state was inconceivable and her later explanations of it were incomprehensible.

The judgment by the Federal Bureau of Investigation director, Mr James Comey, that her handling of the e-mail messages was "extremely careless" was, to the intelligence tribe, a huge understatement.

Mr Donald Trump has never been exposed to state secrets, so the issue is not that he may have been careless in the past. It's just that he seems to say anything that enters his head at the moment. That's a danger for someone who will now be living partly in a classified world.

But with Mr Trump, the issue goes even deeper. Earlier this week I joined 49 other former national security officials who had served in Republican administrations in declaring that he lacked the "character, values and experience" to be president. Our letter noted that "being willing to listen to his advisers" is crucial to a good leader's temperament. That temperament will be tested in his first classified intelligence briefing.

Mr Trump has asserted that the Islamic State in Iraq and Syria (ISIS) is gaining strength, questioned the need for Nato, praised President Vladimir Putin of Russia and extolled the benefits of Brexit. Yet, I can picture that he'll soon receive a briefing that will include phrases like recent successes against ISIS, or threats to Nato unity, or Mr Putin's ambitions in Ukraine, or the crippling consequences of Brexit.

Might a briefing change his mind? Probably not. After meetings with Dr Henry Kissinger and Mr James Baker, prominent Republican secretaries of state, Mr Trump said he came away with "a lot of knowledge".

But asked if those meetings had altered his views, Mr Trump simply replied: "No". Yet, such openness to conflicting views is critical for a president who must constantly assess a complicated and ever-changing world.

Mrs Clinton, whose candidacy I am not supporting, presents different challenges. Absent the e-mail kerfuffle, the briefing for Mrs Clinton could well begin with her saying, "Now, where were we?" But it was the director of national intelligence's inspector-general, Mr I. Charles McCullough, who held his ground in saying that some of the e-mail messages on her server were indeed highly classified. Will hard feelings - or lingering concerns about protecting data - strain her relationship with the intelligence services?

The Republican and Democratic nominees will get identical intelligence briefings; no favouritism here. These briefings will not be very specific or frequent.

But all that changes on election night. And that is when the president-elect's openness to information that runs counter to his or her worldview suddenly becomes especially important.

Wednesday morning after the election, a briefing team is going to give the president-elect the daily brief - the real one, pretty much just like the one President Barack Obama will get that day.

Do what it takes to get 270 electoral votes, and you get the real secrets - worldview or carelessness or talkativeness be damned. It's a wonderful commentary on the sovereignty of the people. And the need to vote wisely.

The briefings themselves will be intense. The president-elect will be shown great deference personally, but his or her campaign positions could be treated more harshly. This is the chance for the intelligence professionals to set the record, as they see it, straight.

I had my own such experience. After election day in 2008, I was briefing Mr Obama on Central Intelligence Agency renditions when Mr Joseph Biden, the vice-president-elect, interrupted to observe that the agency had conducted that programme - which entailed sending suspected terrorists to third countries - simply to "rough them up".

I rejected the contention and advised him that he needed to stop saying that. I haven't heard him say it again.

In an intense briefing on Iran with Mr Obama shortly after his inauguration, he asked me how much low-enriched uranium the Iranians had at Natanz, a major nuclear plant where they had thousands of centrifuges spinning.

I thought he was asking the wrong question. I said that I knew the answer and would give it to him in a minute.

But I added that there might be another way of looking at it, that there wasn't a neutron or electron at Natanz that was ever going to be in a nuclear weapon. What the Iranians were building at Natanz, I said, was technology and confidence, something not strictly related to the size of the stockpile. In other words, it was Natanz's operation, not its output, that was most important.

The members of Mr Obama's team took such dialogue seriously. They would go their own way, of course, but they didn't instinctively reject alternative views.

I suspect Mrs Clinton would react much the same.

How Mr Trump - who routinely describes those with alternative views as weak, corrupt or stupid - would respond is anyone's guess. But I'd rather not find out.

NEW YORK TIMES

• The writer, the director of the Central Intelligence Agency from 2006 to 2009 and the National Security Agency from 1999 to 2005, is the author of Playing to the Edge: American Intelligence in the Age of Terror.