Since the 1950s, US presidential candidates from both major US political parties typically begin receiving classified security briefings after their parties’ nominating conventions conclude. Clinton's Republican rival Donald Trump attended his first classified security briefing last week. He was then joined by former Defense Intelligence Agency head Lt. Gen. Michael Flynn and New Jersey Governor Chris Christie.
Earlier in August, former Central Intelligence Agency (CIA) and National Security Agency (NSA) Director Michael Hayden said that the domestic intelligence could face challenges and risks working with the next president, whether it was Clinton or Trump, as both could be careless in respect of state secrets.
Among the reasons for concerns, Hayden cited Clinton's email server scandal and Trump's habit of speaking directly what is on his mind.