MA*SH (television)/WMG

There are multiple MASH universes

Think about it, the show starts in 1952. Later on it is 1950. An explanation for this is that the show is actually multiple alternate universes. Each universe has differences. In one universe Colonel Potter didn't show up until 1953. In another universe Henry Blake was sent home very early in the war. This would also explain why in some episodes Hawkeye is from Vermont, his mother is still alive, and he has a sister. Several MASH universes exist.

Colonel Flagg appeared in disguise in the episode Deal Me Out

Colonel Flagg was a self proclaimed master of disguise and CID man. In the episode Deal Me Out a CID man, played by Edward Winter, appeared and played Poker with several people including Sydney Freedman. In the episode Quo Vadis, Captain Chandler, Flagg asked Freedman, "Didn't we play poker once?" Flagg wanted to survey the 4077 in Deal Me Out, hence the disguise.

The 4077th is a 1970s zone in 1950s Korea.

Think of The Brady Bunch Movie and how the Bradys were still stuck in the '70s during the '90s. Well, M*A*S*H is the same thing, but in reverse. It's the 1970s at the 4077th, but everywhere else it's still the 1950s.

Think about it. If people stayed at the 4077th long enough, they developed '70s sensibilities, '70s hairstyles and a supply of pop culture references that postdated the Korean War. For instance, patients regularly went into the camp with '50s views and left it converted to a '70s way of thinking. In the case of Frank Burns, he attempted to maintain his '50s views while constantly living in the '70s zone and naturally went mad. Also, consider B.J.'s look when he first arrived and how his look changed after he absorbed enough of the '70s atmosphere.

Meanwhile, military officials outside the '70s zone were totally baffled by the 4077th since they could only relate to its members with a '50s mindset. As for Dr. Freedman, he only started to fit in at the 4077th because he hung out there so much. Remember he was actually a bit of an ass when he was first introduced on the show.

Except Sidney really wasn't that much of an ass, he got along well with Hawkeye, Trapper, and the rest of the crew, he's such a nice guy he can even be nice to Frank. At worst he was mildly surprised and privately amused at the shenanigans going on at the 4077th, which never really changes. The worst thing he did was he took Klinger's own schtick and turned it against him to get him to (temporarily) drop his request for a section eight, which was exactly what Henry wanted anyway because the fact of the matter is no matter how much trouble Klinger causes he's still a good soldier and medic who doesn't allow his antics to get in the way of his duties.
Also, this area is still 20 years ahead, and suffers from a high rate of car theft due to the South Korean auto industry stealing specimens of their own future products to reverse-engineer. This explains why Korean cars improve by leaps and bounds with each new generation but never quite catch up to Japan and Europe.

The 4077th is trapped in a Groundhog Day Loop

This explains why years keep repeating. It also provides an explanation for the above theory: the 4077th went through so many permutations that they advanced onwards to the 1970s, leaving the rest of the world back in the 1950s.

Except in this loop, the people keep aging, a condition that's unknown to them. That's why they continued to refer to Radar as a kid when he was already 37 years old. This would also explain why the patients that were treated at the 4077th got older as the season wore on, too.

All the temporal continuity issues in MAS*H and any disfavored episodes can be attributed to Hawkeye's delusional mind.

Technically, this could go as far as it needs to, in order to fit the series into the time frame of the Korean War.

It also explains why the later episodes became more and more about him, as he descended further into self-absorbed madness.
It would also explain the increasing darkness and intensity of his breakdowns, from just making one up in a Season One episode to being bent and broken for good in the grand finale.
Or... He is in fact in a 1970s mental hospital, reliving distorted memories of his Korean War experiences. This would explain both the numerous anachronisms and the inconsistent time-looping.
- And the glimpse of the mental hospital we get in the last episode is actually the only thing that is real, it's an actual 1970's mental hospital. Sidney Freedman is Hawkeye's 1970's doctor, whom Hawkeye retroactively inserted into his memories as Sidney questioned him about them. The therapy was obviously unsuccessful, as instead of being released into normal life Hawkeye descends even further into hallucinatory madness and fantasizes that he has returned to the 4077th.
  - But in the end Sidney himself sends Hawkeye back, suggesting that even if it is a hallucination of his delusional mind he still has business there he must take care of before he can ever leave and move on with his life, most likely the repressed memory and the final operations he performed on people who very likely never made it. He had to confront the fact that he couldn't save everyone and the fact that peace doesn't mean people stop dying. Sidney leaves the O.R., realizing that this is something Hawkeye must confront alone if he's ever to have any kind of closure. In the end Hawkeye not only leaves the 4077th, but Korea, which would suggest that he's made his peace with all he experienced there and can finally start to pursue a normal life.
    - Or, instead of being sent home, he still has issues resulting in a second breakdown, and is sent to a mental insitution shortly after the events of the finale. Sidney was real and was his doctor in the Korea, he just remembers Sidney well into the '70s.
      - Or, everything, including his final breakdown and war's end, are memories. He just inserted his current doctor-Sidney- into his memories.
Alternately, an aging Grandpa Pierce is telling these stories to his grandkids as wartime anecdotes, and he's long since lost track of when their events took place and which of the accounts he just made up. The 1970s or post-70s attitudes are a result of him adjusting the stories to suit, first his kids' tastes, then his grandkids'.

It's all a psych test

After the war ended, the American government made a deal with Korea, or had them bug out to a neutral zone, because the group had been chosen as a test group to see how long a bunch of people could be kept in a hostile combat zone before they would be more sad to leave than happy to go. The characters who were removed without being pronounced dead, such as Trapper John, had either figured it out or were throwing off the statistics. There were multiple groups subject to this test, and they happened to be one of the groups that were told the war was over after an extra 12 years, and had a bunch of stuff happen that would test the remains of their sanity (The "chicken" on the bus was a final way of hitting the most upbeat person where it would most hurt their spirit, and why do you think Father Mulcahey wasn't hit by any shrapnel, just a shock wave?) This is, of course, entirely justified by the idea that American government agents are allowed to be sadistic psychologists, if it's in the name of "science" (or at least with a decent excuse).

Alternately, it's not the 70s at all: it's actually a test being done in the future, far enough ahead that they don't actually know the difference between '70s culture and '50s culture. They were (will be) using different sets of clones with the same sets of memories, and the same "title" for each character- Hawkeye for the happy-go-lucky manic-not-depressive surgeon, BJ for his Put on a Bus partner and BJ for his replacement, Burns for the belligerent thinks-he-knows-it-all, Hollihan for the snarky love interest. Two of the same O'Reilly series clones (Radar) happened to be used for the groups of the movie and the television series.
For this theory to work, it would have to explain the source of the hundreds of wounded soldiers that the 4077 treats. Researchers could be remorseless sociopaths back in the day, but it seems unlikely that they'd intentionally critically wound hundreds of people just to maintain the illusion.

MASH and The X-Files are set in the same continuity, and either Bill Mulder or the CSM was Major Flagg (Ed Winter's character) from MASH

This theory depends on how much of the Cigarette Smoking Man's back story (as shown in "Musings of a CSM") we accept. The theory depends on the similar characteristics and back stories of X-Files characters Bill Mulder and the Cigarette Smoking Man (CSM) and M*A*S*H's Colonel Flagg. Bill Mulder was an agent of the Cigarette Smoking Man who worked with the Conspiracy. If we accept CSM's early back story from "Musings," we also have the fact that both CSM and Bill Mulder knew each other when they served in the Army in the late fifties/early sixties. Earlier in his career as an MIB, Bill Mulder had hunted communists in the State Department. Flagg was a mysterious military MIB who impersonated other officers, carried out secretive and sometimes self-contradictory missions, spoke in hyperbole and threats, and was obsessed with hunting communists. He came with loads of fake IDs, so we can safely guess that Flagg wasn't his real name. It was either (Bill) Mulder or the nameless CSM.

Also, it is common knowledge that M*A*S*H and The X-Files take place in the same universe.

Further similarities between The X-Files and M*A*S*H include:

Paranormal activity: both shows frequently featured near-death experiences, one episode of M*A*S*H featured the disembodied, self-aware ghost of a dead soldier and suggested the existence of an afterlife. Father Mulcahy often pulls off miracles. And Klinger once ATE A JEEP. The 4077th is located in the Korean version of the Bermuda Triangle where the camp is unstuck in time, fluctuating between the fifties and the seventies, for eleven years throughout a two-year long war.
Don't forget Radar's ability to hear things long before anyone else could and how he knew what everyone was going to say before they said it, even to the point that they would have to come up with something else to try to trick him.

Colonel Flagg is actually Stephen King's Flagg

Problem is, his usual methods of sowing chaos for The Red King only work on people who take themselves too seriously, like the weaker minds in The Stand and The Dark Tower, or Frank Burns. He was forced to resort to the oft-cited temporal whammy on the medics, but it left his form in the MASH universe in a state of growing increasingly caricature-like. Like faith for those in The Stand, and like ka for those in The Dark Tower, the 4077th's sense of humor broke the Walkin' Dude's power there.

Colonel Flagg is Rick Flagg Senior.

He was secretly evaluating Pierce for recruitment in the 1950s Suicide Squad.

Klinger doesn't want to get out on a Section 8. He just wants to be the center of attention.

With all the talented people in the unit, Klinger needed a gimmick to get attention. Compared to the doctors, nurses, and even Radar who was a gifted clerk with a kind of clairvoyance, Klinger could have faded into the background if he didn't have something to get everyone's attention, so he started wearing dresses and pretended he was trying to get out for being crazy. Any time one of his stunts came close to working, Klinger would sabotage himself. When Radar left, Klinger became the clerk and suddenly everybody needed him. With his need for attention satisfied by his job, he was able to stop wearing dresses and stopped pretended to try to get out of the Army.

More evidence of this appears when the doctors are about to go make a swap of wounded prisoners. When Klinger finds out, he volunteers to drive the bus even though Radar was already going.
Sidney Freedman actually offered Klinger a discharge at one point, and Klinger refused it ostensibly because he would be labeled a homosexual in the discharge papers--after he had spent his entire military career trying to convince everyone he met that he was a transvestite.

MAS*H takes place in an alternate universe where the Korean War lasted for almost 9 years longer than it did in the is reality.

The proof? The overly lengthy war...the even lengthier hairstyles not in fashion in this universes' 1950's...the surprisingly modern views towards women and minorities...the lack of smoking in later episodes....the lack of military discipline or order...and the relative lack of friction between the Korean population and the characters. Clearly this show was not set in this universe....

Radar is a Mutant.

Or at least has ESP and/or some kind of psychic abilities. Both the former and the latter have been explored in Fan Fiction.

Radar is autistic or possibly retarded.

This would explain how he was seemingly wise for a kid in early episodes, but then regresses in later episodes. He's also fairly good at complex problems at times, but then can't accomplish everyday tasks.

Despite being in his 30s, he thinks of himself as a 15-year-old kid. That's why he gets shy around women and can't drink alcohol.

That's ridiculous. Radar was just a socially awkward, developmentally stunted young man who possessed unusually strong organizational talents and had almost supernatural auditory perception. That doesn't mean--holy crap, you're right! Radar had Asperger's!

The 4077th is purgatory for army medics

Just like Life On Mars and Ashes to Ashes provide purgatory for Coppers, so the 4077th gives a place for those army doctors and corpsmen who have seen too much to work out their issues and move on. That is why it is a mishmash of 50s-70s stuff.

Hawkeye and Trapper pretend to be opposed to the war, but in reality, they're communist sympathizers.

I think Frank was onto something when he accused Hawkeye of mutiny and attempted to have him court-martialed. Examples:

When Frank gets an anti-aircraft gun, Hawkeye sabotages it to keep Frank from shooting down a North Korean plane that has been dropping (by hand) small bombs near the camp.
After sabotaging Frank's efforts to shoot down the enemy plane, Hawkeye and Trapper guide his AA crew to aim for the ammo dump, resulting in its destruction. They have no concept of what the lost ammo would mean to US troops in the sector.
When a soldier pays off a gambling debt with a piece of artillery, Hawkeye sabotages it. He claims he did it because the gun's presence was drawing North Korean fire, but sabotaging the gun doesn't change it's presence. It just keeps it from being used later to kill North Korean soldiers.
When a lone North Korean sniper shoots at the camp, Hawkeye comes up with a plan to surrender, and he and Trapper attempt to surrender the entire camp to the lone soldier.
Hawkeye refuses to fire his weapon at the enemy even when the enemy is firing at him.
Hawkeye and Trapper operate on North Koreans and Chinese before operating on Americans, sometimes using valuable supplies on North Koreans instead of using them on Americans.
They falsify documents to get willing, effective soldiers sent home, but send cowards, homosexuals, and racists back to the front, probably to sabotage the units, knowing the presence of cowards, homosexuals, and racists is bad for morale.
Hawkeye helps a North Korean doctor slip into character and assume an identity as a South Korean doctor, then helps him get transferred to a South Korean unit.
They replace Frank's weapon with various other items, including a toy pistol, possibly in an attempt to get Frank killed.
When the doctors go to do a prisoner swap at Rainbow Bridge, Hawkeye and Trapper try to befriend the enemy and seem at-ease with the North Koreans and chastise Frank for disliking them. This gives the impression that Americans with guns are bad, but North Koreans with guns are okay.
When Trapper's friend (an intelligence officer) visits the camp, Trapper and Hawkeye get him into conflicts with Colonel Flagg, wasting the time of two intelligence assets that could be working on the war instead of wild goose chases created by two doctors.
Hawkeye stands by his Hippocratic oath when he doesn't want to do something, but dismisses it if it lets him do something he wanted to do, like drugging Frank so he can throw a party.
On their second run-in with Flagg, Hawkeye and Trapper stop Flagg from taking a North Korean prisoner to Seoul by putting Klinger in a stretcher in the prisoner's place. What happens to the prisoner after that is not revealed in the episode, but knowing Hawkeye, they probably fixed him up in a South Korean uniform and got him a job in a South Korean unit.
When Hawkeye is the pay clerk in Payday, soldiers approach his table and salute him. Instead of returning the salute, Hawkeye raises his right hand in a limp attempt to wave, but this actually looks more like the Nazi indoor heil.
- I don't think I understand what this last point has to do with him being a Communist sympathizer? I suppose that he is associating the U.S. army with fascists? I realize this is all in good fun, but I find it odd and troubling, the implication that being critical of the U.S. military means one should be suspected of being a traitor. Isn't it interesting that, in the 70s, a popular sitcom could have a conscientious objector as its key protagonist? Would this fly today?