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35 years ago, the Texas oil baron J.R. Ewing was working late at his office when he was shot twice by a mysterious assailant. J.R. crumpled to the ground with his fate unknown, and every member of the cast a plausible suspect in the shooting. With that, the third season of CBS’s Dallas concluded, but at the same time, it also graduated from hit network show to nationwide phenomenon.

The end-of-season cliffhanger, deployed so effectively in 1980 that “Who Shot J.R.?” became a national catchphrase, is a brilliant and oft-used television device. But in a fractured TV landscape that no longer takes the summer off, it's a ploy that struggles to punch with the weight it once did. Dallas aired during the golden era of the “big three” TV networks, when there was no way to binge-watch and catch up with the hit of the moment. So its third season finale was an innovative gambit—the cliffhanger was the stuff of serialized soaps and Charles Dickens, not the world of episodic television, where mysteries were tidily solved every week.

"Who Shot J.R.?" was hokey and not particularly compelling from a writing standpoint—almost every character on the show had a reason to shoot the manipulative and unscrupulous patriarch, so it was almost beside the point when Dallas revealed who actually did it eight months later. But it was the kind of water-cooler moment that could drive conversation about the show during the quiet summer months of the network TV schedule. Dallas was serialized television, but not so much that viewers couldn't jump right into any given episode and figure it out, and after a few months of hearing co-workers or family members debate their theories about potential suspects, it was hard not to. The show ended its third season as the sixth-most watched show on television, with 19.1 million viewers; its fourth season jumped to number one, with 27.6 million people watching. The reason for that kind of meteoric leap in ratings is indisputable.

The storyline's success wasn’t thanks to Dallas's quality, or America's fondness for star Larry Hagman, who’d turned a secondary character into the archetypal man-you-love-to-hate, and the breakout star of the show. The third season finale "A House Divided" aired on March 21, 1980, and Dallas didn't return to screens until November. Over that summer, Ted Turner's fledging Cable News Network launched, and embarked on the then-daunting concept of reporting the news 24 hours a day—with feverish speculation over J.R.'s assailant becoming a popular and frequent topic.

As with many classic TV cliffhangers, the show's writers went into things with no particular idea of how to resolve the mystery, arriving at the conclusion just by a logical process of elimination. Another example of that loose approach is "The Best of Both Worlds," the third-season finale of Star Trek: The Next Generation, which ended with Captain Picard captured by the alien Borg and transformed into a cyborg zombie. The writer and showrunner Michael Piller later admitted he had no concept of how the next episode, which led off the fourth season, would resolve the cliffhanger—he just knew the show needed something to keep audiences on the hook over the summer. The Next Generation was a steady cult hit before the episode, but its ratings jumped by 25 percent between seasons, and the show graduated to mainstream success.

This isn’t to argue that cliffhangers belong to some bygone age of television writing. But the traditional September-to-May scheduling of the glory days of network TV certainly does, and with its decline comes adjustments. The summer is no longer a period of dead air around which buzz for the fall schedule can build. The TV landscape is constantly littered with new entrants, emerging mini-networks, and strangest of all, old shows being sold into syndication for streaming services—now, a whole new generation can be surprised by Picard's capture while watching on Netflix, except there's no need to wait three months for the conclusion.

AMC's Breaking Bad was a show that harkened back to the glory days of edge-of-your-seat mysteries, ending every season with a bombshell shot (a plane exploding in the sky, Jesse Pinkman pointing his gun at the camera) and many tantalizing dangling plot threads. But the show didn't find ratings success until it popped up on Netflix; its highest-rated episode by far was the series finale, which drew 10 times the viewership of any other season finale the show aired. Audiences could now wait for almost the entire show to be ready for binging before watching the final episodes live. America's patience for long TV layovers, it seems, has significantly waned.

This is, perhaps, where the increased debate over "spoilers" has come from. In 1980, if you wanted to know who shot J.R., there was only one way to find out: tuning into CBS on Friday at 10 p.m. Now, a push notification on your phone can tell you what happened on The Jinx right after HBO airs the episode, and fans will complain about years-old plotlines being ruined in articles online because they haven't gotten around to binge-watching that particular show yet. The pop-culture website The A.V. Club continues to publish two different reviews of Game of Thrones every week—one for fans who've read the books they're based on, and one for "newbies," just to avoid plot revelations being discussed in their respective comment threads.

Along with Thrones, the most famous cliffhangers of the last 10 years have come from ultra-serialized genre dramas like Lost (the season three revelation of flash-forwards) or Battlestar Galactica (the season two time-jump that saw humanity's new colony conquered by the Cylons). Network shows are more content to vaguely set up next year's plotlines without tying the writing into one particular mystery that needs to be solved. This season's biggest ratings hit, far and away, is Fox's music drama Empire, which creators Lee Daniels and Danny Strong have repeatedly compared to the grand primetime soap operas of the past, often citing Dynasty and Dallas as their main inspirations.

Empire concluded its first season Wednesday night with many a surprising plot development (and indeed, beware of spoilers), including Lucious Lyon (Terrence Howard) handing his business over to his son Jamal before being arrested on a decades-old murder charge. For a show that's vaulted into the zeitgeist partly on the back of its breakneck plotting, this final twist seemed tepid; no doubt Lucious will be out of prison soon enough and working to take back his business. If the show had simply repeated the 35-year-old trope of "A House Divided," with Lucious walking out of his office only to be gunned down by a mysterious assailant, no doubt the show's fans would have taken the bait and discussed the many, many suspects during the drama’s months off.

But that kind of gimmick might not be necessary anymore. The whodunit cliffhanger is an arresting device, but has become increasingly cheapened over the years; why write a show into a corner when you can have as many plot avenues open as possible in the future? That doesn’t mean the end-of-season twist has completely lost its value—just its ability to gut-punch. Olivia Pope was kidnapped on last year’s Scandal finale, but no matter how dire things might have looked, it’d be hard to convince audiences she was in danger of being written off the show. More common still is the cliffhanger that promises more great storytelling to come: think of newly-minted President Frank Underwood looking at the camera and pounding the desk at the end of House of Cards’ second year. “Who Shot J.R.” was a wonderful gambit, but that's how it's remembered: as a clever ploy to keep viewers watching, not a masterful display of craft.

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