If makers of miniseries and made-for-TV movies felt the squeeze when their Emmy categories merged two years ago, they’re inhaling more deeply now.

A few players from the hourlong series world, including FX’s “American Horror Story,” have migrated from the drama categories to the movies-and-miniseries competition, where they will compete with projects from HBO film “Game Change” to History’s six-hour mini “Hatfields and McCoys.”

The moves not only affect this year’s m&m categories, including writing, acting and directing, they conceiviably crack the doorway for some canceled series to direct their Emmy bids far from the heated drama competition. While an onslaught is unlikely — drama retains considerably more Emmy submissions — some argue that the latest development corrupts this portion of the Emmys.

In 2010, HBO miniseries “The Pacific” and telepic “Temple Grandin” each won Emmys in their separate categories. Last year, had they competed in the merged competition, only one could have won. This year, there would be the possibility that neither would.

TV Academy member Leslie Greif, whose long producing career in television straddles the genres in question — from ’90s drama “Walker, Texas Ranger” to this year’s “Hatfields” — was already disturbed when the org lumped minis and movies together, because they involve different tools and challenges. The latest twists add to his frustration.

Greif says it’s not about one’s chances of winning, noting that the nominees, whoever they are, will always be top-notch. Rather, he argues, the integrity of the Emmys is being undermined, in that they’re not evaluating what they’re supposed to be.

“I feel that it’s disheartening that the powers that be have been able to manipulate a system based on their clout to serve their needs,” Greif says. “It rocks the foundation and the credibility of what we have established as guidelines for the different categories.

“In the end, it seems obvious from the people I talk to that it’s just networks positioning themselves to try to garner more Emmys.”

“Missing,” starring Ashley Judd, and fellow ABC skein “The River” were each conceived as regular drama series, but used their cancelations as an escape from the drama races. The programs essentially became series of finite length, enabling them to meet the definition of miniseries.

“American Horror Story” weaves a different tale. That program is actually returning to FX in the fall, but is wiping the slate clean with a whole new batch of characters — something that FX prexy John Landgraf says was intended all along but kept on the QT.

That makes its first season a self-contained one, though it does raise the possibility that “Horror” could become an oxymoron: a perennial miniseries.

“We didn’t want to tell the audience going in that (the first season) was a closed-ended story because we didn’t want to ruin the surprise and have people know that the many characters they were watching wouldn’t be coming back in subsequent seasons,” Landgraf says. “It’s so rare in television these days that you can actually have an experience that’s surprising.”

The TV Academy must offer its blessing, but once it does, a show that is eligible for both drama and movie-miniseries can determine its own Emmy destiny.

“The producers of ‘American Horror Story’ came to the Academy,” says the org’s senior awards veep John Leverence, “and they said, ‘We have a situation here which is neither fish nor fowl — that is, a story with a beginning, middle and end. And then we have in the works another version of it next year, but it’s going to be, other than the themes, something completely different.’ ”

“American Horror Story,” “Missing” and “The River” thus enter a field that also features such British imports as BBC America’s “Luther” and “The Hour.” Even in its second year, “Luther” and 2011 Emmy nominee Idris Elba must remain in the miniseries category, because a minimum of six episodes are needed for drama category eligibility and only four were made.

On the other hand, “The Hour” is staying in miniseries despite having enough hours to qualify for drama — not to mention a second season already scheduled.

That echoes the year-ago situation for the program that became 2011’s Emmy miniseries-movie champ, “Downton Abbey.” This year, “Downton” is making its own move. Conceived as a miniseries, the British program (airing Stateside on PBS) became so successful that once it became clear that it would run for multiple seasons, its producers decided not to pretend it was different from any other drama series.

“There was one opinion that you stay in the category you started in,” says “Downton Abbey” exec producer Gareth Neame. “But we took the opinion that, how could we argue that ‘Downton’ was still a miniseries? We feel that it’s now a returning episodic series, and I think because the show has broken out to such a degree in the U.S., it is talked about in those terms, so we really ought to be in that category.”

The move of “Downton” to drama takes year-ago Emmy-winning director Brian Percival and writer Julian Fellowes, as well as acting nominees Elizabeth McGovern and Maggie Smith with it, not to mention such potential nominees as Michelle Dockery. It’s unclear whether “The Hour” might follow suit in 2013.

But while a miniseries or TV movie becoming a drama series might happen from time to time, every year brings multiple soon-to-be-canceled drama series that fit the description of “Missing” or “The River.” And while one could argue that the mere fact of cancelation limits their Emmy prospects against prestige projects such as “Game Change,” the possibility of a so-called “brilliant but canceled” drama taking a spot in the miniseries race is certainly growing — especially if broadcast networks shrink initial orders to the level common with cablers.

For the time being, the trend hasn’t gripped all the networks. Fox could have made a case for “Terra Nova,” NBC for “Awake,” but neither is biting. HBO, which abruptly canceled “Luck” after its nine-episode first season following the death of a horse during filming of an early season-two episode, is keeping that series in drama as well.

For his part, Landgraf makes it clear that he doesn’t envision canceled series, such as 2010-11 FX dramas “Terriers” and “Lights Out,” as anything but dramas.

“Those aren’t miniseries,” Landgraf says. “We wouldn’t do that. A busted series isn’t a miniseries. … You have to have intended to end the show and not end it unintentionally.”

But while saying that he loves “American Horror Story,” calling it “terrific,” Greif still questions its presence in the category, citing language from FX’s promotions and official website as evidence.

” ‘Season finale,’ ” Greif says. ” ‘Season one’ … implying another season. Not ‘series finale.’ They refer to favorite episodes, but episodes are with series.”

The kicker, of course, is that some Academy members would prefer further division at the Emmys for programs, actors, writers and directors in minis and movies, rather than contraction.

“I understand that because … there were fewer movies and minis made, that they made an effort to group them together,” Greif says, “but I do feel they are two different art forms.”