Calls have increased for Republican nominee Donald Trump to be denied national security briefings offered to presidential nominees of major political parties after he said he hopes Russia is "able to find" Democratic nominee Hillary Clinton's discarded private emails.
Senate Minority Leader Harry Reid said he hopes the candidate is given "fake intelligence briefings … because you can't trust him."
And Democratic Rep. David Cicilline of Rhode Island has sent a letter to President Barack Obama saying Trump "is unfit to receive sensitive intelligence" and asks that he "withhold" Trump's expected intelligence briefing.
A petition by the liberal group CREDO has amassed more than 80,000 signatories in less than 24 hours urging that Trump receive no security briefings.
Can Donald Trump - or any presidential nominee - lose access to briefings on national security?
In short, yes.
The national security briefings are "a courtesy" and a "tradition," according to David Priess, the author of "The President's Book of Secrets," about the president's intelligence sessions.
The briefings, usually numbering one or two at a mutually agreeable secure location any time between the nominating conventions and Election Day, are given at the discretion of the president and not mandatory or required by law.
They began in 1952 under President Harry Truman, who offered the service to Republican candidate Dwight D. Eisenhower. Truman, who felt completely unprepared when he entered office in the middle of a war, believed no future president should be ignorant of intelligence matters.
Only George McGovern in 1972 and Walter Mondale in 1984 did not receive the briefing. McGovern and the briefers had scheduling conflicts that couldn't be resolved and Mondale turned it down because he didn't think he was going to need it because he didn't think he was going to win, Preiss said.
Who conducts the briefings?
For the first 52 years, the CIA gave the briefings, but since the 2004 election, the Office of the Director of National Intelligence has, which include a printed briefing book for the candidate.
James Clapper, the current Director of National Intelligence, said he would conduct the briefings himself.
Will President Obama allow Donald Trump to be briefed?
White House spokesperson Josh Earnest said Thursday that the president is going to stick with "tradition that's been in place for more than 60 years."
Clapper said at the Aspen Institute in Colorado Thursday that "now is the appropriate time since both candidates have been officially anointed that both campaigns, camps, will be reached out to and offered briefings."
Could briefers give "fake" intelligence or watered down information, like Reid suggested?
Earnest also said that sensitive information must be protected. "The administration is confident they can both provide relevant and sufficient briefings to the two major party presidential candidates, while also protecting sensitive national security information," Earnest said.
There is no indication or evidence that briefers would ever or have ever provided "fake" information. Priess said "it's possible" that a candidate would receive "a more generic" briefing, but the point of the modern-day information session is to ensure that a candidate doesn't say anything that would damage foreign policy on the campaign trail - or box him or her in should the candidate win.
Briefings do not include information about espionage, covert actions or nuclear information.
"Candidates are advised of the classified nature of the material, and operational and policy matters are not addressed," an intelligence official familiar with the matter told NBC News.
Gov. Michael Dukakis said the two briefers who came to his home during his 1988 presidential run were then CIA Director William Webster and Robert Gates, then Deputy Director of the CIA. Dukakis described that Reagan administration briefing as not very illustrative.
Could Clinton receive a different briefing than Trump?
It is not likely that the candidates would receive different information in their briefing.
"Briefings for the candidates will be provided on an even-handed, non-partisan basis," the intelligence official said.
Earnest also said he expects there will be no difference.
"Director Clapper also publicly indicated that his expectation is to provide the same information to both nominees. That certainly seems appropriate," Earnest said.
Who gets the briefings?
In addition to the presidential candidates, the vice presidential nominees are also briefed.
For instance, during the 2004 election, Sen. John Kerry was intrigued and engaged but his running mate, John Edwards, was not that into it. "
"CIA briefers … heard Edwards tell his staff as he approached the briefing room at the hotel, 'I know I have to do this, but I will get it over with quick and we can go for pizza.,'" according to John Helgerson's book, "Getting to Know the President," a history of intelligence briefings of presidential candidates.
Candidates are also able to bring in top staff.
What if a candidate spills classified information?
The candidate and his or her national security staff in the room do not have to have security clearances.
If a candidate divulges classified information, there could be legal repercussions but the political repercussions would probably be far worse, according to Preiss.