Twenty years ago US network TV was edited on film, yet the deadlines were as scary as they are today.
Check out this interview with the post supervisor on Moonlighting. They were shooting on Monday morning for a show that went out on Tuesday night:
But this editor said it was the strangest experience for him because he came into work, edited all night, went home, went to sleep, woke up and turned on the TV, and it was on the air. It was as though the network had just plugged a big cable into the back of the moviola.
There are many other interesting things in this article, including the use of music, stunt doubles, ordering music by the yard and using the emotion of a scene help the editor know who to to favour. Also there is a great deal on the editorial choices in the making of Boston Legal.