Historian explains journalism: Ron Chernow gives White House correspondents a history lesson, writes Michael M. Grynbaum, on why journalism is important.

“Freedom of the press is always a timely subject and this seems like the perfect moment to go back to basics,” Chernow wrote in a statement.

Chernow avoided offensive comments of the sort delivered by comedians invited in the past to the correspondents’ dinner, directed at politicians invited as guests.