When "The Hangover Part III" hits theaters this Thursday, fans across the country are expected to line up, settle in with some popcorn and enjoy some deep belly laughs courtesy of the wild antics of Zach Galifianakis' one-man wolfpack, Alan Garner.

But there's one thing different this time around compared to 2009's "The Hangover" and 2011's "The Hangover Part II:" Alan not only has explicit intellectual disabilities, his condition is actually the focus of the plot.

So is it still cool to laugh at him? Or is "The Hangover Part III" simply the latest example of Hollywood's long struggle with how to portray the intellectually disabled?

It's a question that has been building ever since "The Hangover" came out four years ago. In the first film, though, Alan's oddball antics were just a side note in an ensemble piece; for instance, wikipedia (the arbiter of all knowledge in the internet age) simply describes Alan as "socially inept." Hey, we've all been there.

Once Galifianakis became the breakout star, though, Alan got a much larger, central role in "The Hangover Part II." And that's where things started getting a little dicey. Some fans and critics still laughed, but others were uncomfortable with the character's increasingly obvious mental disabilities being played for yuks. "Instead of merely being socially awkward, Alan seems abusive and almost dangerously deranged," NPR observed, while IGN noted that Alan "is borderline mentally challenged at times here, which makes him more sad than funny."

Rather than taking those criticisms to heart, though, director Todd Phillips and company decided to go the other direction, as the trailer for "The Hangover Part III" shows. Not only is Alan's intellectual handicap being played up to the hilt, it's actually the centerpiece of the plot, which kicks off with the gang holding an intervention in an attempt to deliver Alan to a mental institution:

Of course, Hollywood has long faced the tricky dilemma of how exactly to portray the intellectually disabled in film. And in some ways there doesn't seem to be a right answer, because with a topic this sensitive, someone is bound to be offended no matter what.

Take, for example, the 2001 drama "I Am Sam," which tells the story of an intellectually disabled man fighting to retain custody of his 7-year-old daughter. Reviews, as they say, were mixed: Sean Penn earned Screen Actors Guild and Academy Award nominations for his role as the titular Sam, yet the film as a whole was widely panned, earning bon mots such as "manipulative," "insipid" and "shameless" from critics. The film "reduces Penn... to a mugging embarrassment," according to USA Today.

Another instructive episode in Hollywood's struggle with the intellectually disabled is Cuba Gooding, Jr. in 2003's "Radio." Gooding won an Image Award for Outstanding Actor in a Motion Picture. He was also nominated for a Razzie for Worst Actor for the same role. "Gooding once again embarrasses himself in public with a performance that knows no shame," the Washington Post said, while USA Today pitched in that "'Radio' comes off as manipulative of its audience and exploitative of the mentally challenged." Yet despite the critical thrashing Gooding and "Radio" endured, the film was based on a true story and the character on a real person who was consulted on the film and appeared as himself in the epilogue.

This highlights the central dilemma facing Hollywood: Any attempt to portray the intellectually disabled, no matter how sensitive or well intentioned, can and will be seen as manipulative by some segment of the audience. Which makes sense, as in some ways that is Hollywood's job, to create and manipulate viewer emotions through the medium of cinema. But are intellectually disabled characters fair game? Where is the line? Or should there even be a line?

Ironically, perhaps the most famous (or infamous) discussion of Hollywood's treatment of intellectually handicapped characters took place not in clinical journals or critical discussions but in the 2008 comedy "Tropic Thunder" (note: this clip is NSFW and potentially offensive to pretty much everyone alive):

Both of the films cited by Robert Downey, Jr., "Rain Man" and "Forrest Gump," were critically acclaimed, award winning films. Both also had their detractors; as Debatewise concisely summarized, "Rain Man" had "bad press in the autistic community for giving people a stereotype of a person with autism - a secret genius with a hidden gift, but completely inept at everything else - that is inaccurate and widely believed." Yet at the same time, it began a public debate about autism, which at the time was barely known to the general pubic and which now is widely recognized in part due to that pubic debate.

Not that we expect "The Hangover Part III" to kick off a similar debate regarding its treatment of Alan. But while the idea of wringing laughs from the plight of the intellectually disabled is morally squicky at best, it is perhaps notable that in recent years, comedies such as "Tropic Thunder" and Johnny Knoxville's controversial 2005 film "The Ringer" have provided some of the most honest and surprising commentary on the way Hollywood treats the intellectually disabled. Which is that the intellectually disabled have a "plight" to begin with and are separate from us rather than just being another part of society.

For a question like this, there are no real answers, except one: Good movies are their own justification. They can change the way people look at themselves. A good laugh often does more than good intentions.

So here's hoping "The Hangover Part III" ends up being a pleasant surprise. Because until society begins laughing with the intellectually disabled instead of at them, the joke is on all of us.