What was the purpose of the taping system in the White House? Why would Nixon want everything he ever said as president to be recorded? Surely he knew that this created a record of things that he wouldn’t want to go public.
And, what was the 18 minute gap about? What could have that conversation revealed that the other tapes did not?
All that is known is that the conversation was between H.R. Haldeman and Nixon, on June 20, 1972, and that the conversation included some mention of the Watergate burglary, which had occurred on June 17.
Given the close timing after the burglary and the arrest of the burglars, there is much speculation that Haldeman was giving a very … detailed report to Nixon about the arrest of the burglars. However, it is impossible to know.
The technical panel appointed by Judge Sirica concluded that the erasure was not one single erasure, but at least five erasures, possibly nine, and they could not have been done by the foot control, as suggested by Nixon’s secretary, but by the hand control of the tape recorder.
See the wiki article: the 18½ minute gap.
As to why it was installed - legacy. Nixon was aware that LBJ had a recording system for phone calls and meetings and at some point decided to install a more comprehensive recording system to provide an accurate record of decision making, presumably for the purposes of memoirs or such.
Thing is, when you conspire to break the law and obstruct justice, recordings become a problem.
I think GQ will suit this better.
Joel Achenbach (who wrote a Washington Post column and series of books called “Why Things Are”) addressed this once. He offered several possible answers, but I think the one he settled on was that Nixon could control the narratives about events in his White House by selective editing. He never expected the unedited tapes to see the light of day: a big breakthrough in the Watergate investigation was that the tapes and recording system even existed.
Nixon had no idea that anyone but him and people he authorized would have access to the tapes. It certainly would never have crossed his mind that he would be forced to hand them over to a Congressional inquiry. And of course had the Watergate burglars done their job properly the incriminating tapes would never have seen the light of day.
As for the erasure it boiled down to the word of Nixon’s secretary against that of the technical experts. It wasn’t thought worthwhile to pursue the matter, after all they had Nixon in a corner anyway.
I’ve always wondered why Nixon didn’t erase or destroy all of the tapes once their existence was made known. It would seem fairly easy to do and would have slowed down, although not stopped, the investigation. We’re they his to do with as he wished?
I believe they were subpoenaed as soon as their existence was discovered. Destroying evidence would have gotten him in as much trouble as what was on the tapes.
Yes. Destroying the tapes is definitely equal to obstruction of justice.
As it was, he could try to argue that there was no obstruction of justice. But it’s pretty obvious that the gap involved, you know, obstruction of justice, which is why people removed what it contained.
He should have just ran a bigass magnet over them.
Or actually even co-conspirator discussions!
Possibly, though it’s hard to be conspiring AFTER you’ve accomplished the, you know, conspiracy. 
Committing a larger more extensive crime is your idea of a good suggestion?
The 18+ minute gap was actually a live bootleg version of Iron Butterfly’s In A Gadda Da Vida.
Nixon erased it because he was afraid of Atlantic Records legal team.
Either that or Tricky Dick was doing the vocals himself and didn’t want *that *in public.
Don’t recall if Haldeman ever said his version of the what the missing contents were?
Well it made for a good episode of Breaking Bad.
My wife’s an attorney. Though she doesn’t practice criminal law.
One of her sayings back in the day was “You can parlay a parking ticket into murder one if you try hard enough.” She’d certainly seen many a poor sap make his problems far bigger by doing exactly the wrong thing; doubling down or worse on a badly losing hand.
I don’t know if Haldeman ever testified, but he kept written notes of his meeting and it was apparent from the notes that he discussed the Watergate burglary with the President. His notes did not say exactly what they discussed.
You can always have a “lessons learnt” discussion; you know, for next time. 