You may wonder why Mrs. Clinton, or any politician, is obliged to bring our wretched national press along with them on their airplanes. Mr. Trump does not bring them on his plane, either.

For starters, there’s history. Imagine if reporters had not been on Air Force One when Lyndon B. Johnson was sworn in after John F. Kennedy’s assassination, or on 9/11, when it became a flying, wayward bunker for President George W. Bush. There are moments when you want witnesses to history whose loyalties aren’t tied to the protagonist. So far, Mrs. Clinton’s run as the first woman to become the Democratic Party’s nominee has been observed at arm’s length.

This is about something much bigger than eyewitness accounts and plane rides. It’s about how much we want to know about each candidate’s plans for the White House, and how open and accessible we want them to be as president. And ultimately, it’s about whether we truly believe in the premise that transparency is vital for democracy.

Right now, every signal from Mrs. Clinton is that should she win, her administration would continue the tradition of being still more secretive than the one before it; the Obama White House has achieved just that with its abysmal record on fulfilling Freedom of Information Act requests and its record of prosecuting whistle-blowers who have shared national security information with the press.

Mrs. Clinton’s decision to use a personal email server while she was secretary of state started with an attempt to maintain a level of privacy that, she now acknowledges, backfired. It led to what the Federal Bureau of Investigation director James B. Comey called the “extremely careless” handling of classified information. But it also took thousands of work-related emails out of the official record, exacerbating the State Department’s halting — if not grudging — approach to public information requests.