The column contains spoilers about 'Game of Thrones,' 'The Walking Dead' and 'The Leftovers.' If you’re not caught up, come back when you are.

Three big shows look to have killed off major characters — and then found that dubious fans weren't buying it.

Is this kind of twist the death of good storytelling, just another tool in the tool box or a way to hook an elusive audience? More important, are these twists worth plotting if nobody believes you — if their employment damages the credibility of your show?

Sunday’s episode of HBO’s The Leftovers ended with its main character, Kevin Garvey (Justin Theroux) dying from poison — out cold, heart apparently stopped, white foam coming from his mouth. A few episodes earlier on The Walking Dead, main character Glenn (Steven Yeun), was apparently killed off while pinned on the ground, surrounded by hundreds of zombies. And earlier this television season, Game of Thrones killed off Jon Snow (Kit Harington).

These deaths have not been without their very vocal doubters. But each of them are quite different, and they don’t carry equal creative risk. Maybe the bigger question is: Why would the writers even bother killing off this character if the immediate reaction is likely to be, "I don’t buy it?"

Let’s work backwards on these deaths and assess the likelihood of said character really, truly being dead — and what happens if they do or don’t come back:

Kevin Garvey, The Leftovers: Well, he’s probably not dead. Depending on how much credit you want to give the writers for their knowledge of when and how you can bring back someone who purposely drank poison (knowing there’s an Epinephrine shot to be administered not long after the heart stops), the actual visual tease lasted only a few brief few seconds — as the character who was supposed to "save" Kevin instead emptied out the needle on the ground and then killed himself — before another character stepped in and dragged Kevin away.

Now, this seems like a relatively cheap and easy tease – unlike the two others. We’re to assume that Michael (Jovan Adepo) will somehow save Kevin. So, as shocks go, not much of one. And yet, time is wasting and there doesn’t seem to be a filled-and-ready Epinephrine needle handy and nearby — and do those really work 100 percent of the time anyway? So, yes, The Leftovers is taking at least some risk here.

But no, few people probably believe he’s dead (which would, of course, make it stunning if he did die — easily toppling the other two; but yes, he’s alive).

Verdict: Kevin’s actions are completely believable based on the "psychotic break" he’s experiencing. All told, the storyline makes sense, adds at least a tiny bit of doubt and drama, but otherwise continues down the story path the character will take once he’s revived. I’m fine with it.

Glenn, The Walking Dead: Only Jon Snow and Glenn are truly getting heated reactions via social media. That’s a sign that viewers are torn and they’re annoyed but at least involved. That might be the bottom-most level of validation a writer/showrunner can get, but hey — maybe that’s enough. In any case, Glenn’s apparent death is a very, very big deal for the critical fallout of The Walking Dead — the veracity of the death has by far the most riding on it for the series. That’s because The Walking Dead has been criticized before (many times) about people surviving what look like impossible odds. But in this case, these really are impossible odds. If Glenn survives this, no other death on The Walking Dead can be believed, and that robs from the writers of the show their most powerful tool. If Glenn survives, any future death will have to be so patently obvious as to the outcome that there can be no doubt. And, if Glenn survives, there will be doubt on those future deaths no matter how obvious. No one will ever believe or be fooled again.

Verdict: For me, Glenn needs to be dead. Even though The Walking Dead is a genre series, the show is rooted in its own kind of realism. That realism, in fact, is what makes the series work and when the disparate elements are clicking, it’s one of television’s very best shows (not only one of its most popular shows). However, if Glenn manages to live — and I can’t imagine a scenario that executive producer Scott Gimple could come up with where I buy the fact that Glenn survived — all of that realism is lost. All of it. Like Homeland and so many other shows before it, The Walking Dead can’t use a gimmick that bends reason and plausibility and still expect to be taken seriously.

Jon Snow, Game of Thrones: This is the death that started the War of Dubious Deaths on Twitter, where every day someone is investing in conjecture about whether a character lives or dies, resulting in back-and-forth arguments ad nauseam. The extent of the annoyance is kind of hard to fathom, actually. Sure, Game of Thrones kills off characters for real all the time and keeps them dead, so killing Jon Snow — a beloved character — had a thudding finality to it that fans didn’t want to accept, thus beginning the "he’s not dead” inquest. But this is a fantasy series. All kinds of unbelievable stuff has already occurred — unexplained phenomena is part of the buy-in to all fantastical series. So the ability to bring a man back to life shouldn’t be off-putting as a storytelling device, nor should it hurt the believability of the series in the same way Glenn’s near-death would for The Walking Dead, because A) the construct of fantasy at least makes it plausible, and B) the reluctance of the writers on Thrones to bring anyone back should be an indicator that they won’t be doing this every week.

Verdict: Dead or alive works for me.

The allure of a major character death is great for writers; shock value is a commodity, and used wisely it invigorates a series. It used to be that cliffhanger deaths were used to goose ratings — but both Dead and Thrones are already hits. Maybe they are just trying to stand out (even more) in a brutally crowded field. But the risks are enormous — at least for credibility, which is different gamble than playing the ratings game. Fans want both Glenn and Jon Snow to come back. For the most part, they would forgive the digression and keep watching. Of course, critics may not be as pleased. On The Leftovers, there might not be enough ratings to worry either way. But I think fans of the show would rather have Kevin than not have Kevin. And when I think about how the scenes were shot in The Leftovers, we’re not talking bait and switch shocker here. He’s likely alive.

No, the only real possible damage to a series here can come from Glenn being alive after all on The Walking Dead. If that's the case, it's the most manipulative "death" of the three.

To have all of these characters' controversial demises happen so close together, however — and the instant debate on their dubiousness — suggests writers might want to think of something (anything) different going forward.

Email: Tim.Goodman@THR.com

Twitter: @BastardMachine