This is why Richard Nixon taped his White House conversations

President Trump’s Friday morning tweetstorm about former FBI director James B. Comey has led to speculation that the Trump administration has taken a page from Richard Nixon’s playbook by surreptitiously recording conversations inside the White House.

As it happens, Nixon wasn’t the only president to record his conversations. Six American presidents — from Franklin Delano Roosevelt to Nixon — taped at least some of their conversations. President Ronald Reagan and his successors had several meetings videotaped.

There are a number of reasons presidents might want to have their conversations recorded. Sometimes these reasons overlap.