If the Guardian of Forever is a deus ex machina, then so is the Enterprise.
So are the phasers. The Transporter.
Spock. The Doomsday Machine.
What? That definition doesn’t fit the Guardian in any respect. It doesn’t appear out of nowhere in the final act - it’s introduced in the first, and is a regular presence throughout the episode. It also doesn’t resolve the central conflict. Rather, it precipitates it, by sending several members of the ship into the past, where they’re at risk of destroying the future. In fact, it doesn’t resolve the plot at all - the plot is resolved by Edith not looking both ways before crossing the street. And the solution is not particularly contrived: the plot is, “If Edith lives, Hitler wins WWII.” The solution to the plot is, “Let Edith die.” That’s about as direct a solution to the problem as you can hope for. The strength of the episode as a whole is that the audience is waiting for Kirk to figure out some convoluted solution that lets him save Edith without ruining the future - and he can’t. He has to use the most obvious, immediate solution: let her die as history intended.
Also, the Guardian also isn’t really a MacGuffin, as a MacGuffin is an item that drives the plot, but whose specific nature isn’t really important. The list of agent names in Mission Impossible, the nuclear secrets in North by Northwest, the briefcase in Pulp Fiction, or the recipe for a really good potato salad in What’s Up, Tiger Lily? are all MacGuffins because you could completely change the nature of the contested object, without having to change the plot of the film at all. The Guardian, on the other hand, must be a time travel device, otherwise the plot never happens.
The problem was that McCoy had changed history because the Guardian had sent him back in time. Kind of hard to see what the story would have been without the Guardian. 
The Guardian is really the problem, more than the solution.
Others have explained why you are wrong pretty well, but the Guardian doesn’t even start off a subplot. The Enterprise is in orbit around this planet because the Guardian is emitting time waves or whatever. Almost every ST episode starts off with them meeting something weird. Abraham Lincoln was a lot odder than the Guardian.
And the crucial point is that the Guardian solves nothing. Even letting Kirk and Spock go back in time is not contrived because McCoy going back in time is what led to their problem. So the mechanism for the solution is embedded in the very mechanism of the problem.
If you want to complain about something, complain about Spock not being able to play back the recording at slow speed. What Spock is building is a shift register to slow down the recording - but it would be incompatible and wouldn’t slow it down enough. (I know this because I build something similar for my Bachelor’s thesis.*) But it is fine because it builds tension and leads to some funny lines.
- Yes, I did use stone knives and bearskins.
Well there was your problem!
It doesn’t match the definition of Deus ex machina in any respect. The Guardian did not resolve a damn thing. It was the driver of the story, but the resolution was to let Edith die. The Guardian did nothing other than send the people back in time; they had to solve the problem themselves.
Deconstructing the definition:
“a person or thing (as in fiction or drama) that appears or is introduced suddenly and unexpectedly” The Guardian is introduced at the start of the episode. Nothing sudden or unexpected about that: all stories introduce their elements that way.
“and provides a contrived solution to an apparently insoluble difficulty” The guardian proved no solution. It mere showed that the timeline had changed. It was up to Kirk and Spock to set it right.
If it were a deus ex machina, it wouldn’t show up at all until the final scenes, and it resolve everything without an action by anyone else.
I hate myself for this thought, but here it is: City on the Edge of Forever might be a good seed for a movie in the reboot series. If there’s anything wrong with the original episode, it’s that it was a bit too big an idea for a one-hour episode. It wouldn’t suffer as much from stretching into a movie as most of the other original episodes.
As much as I hate the reboot, I agree.
No one could do the scene in the alleyway as well as DeForest Kelley.
“YOU! WHAT PLANET IS THIS?” :eek:
Then again, if they can fuck up Khan, they can fuck up anything.
McCoy has clearly been reading too much fanfic.*
*or I have.
Amen, Brother!
Yes, he was very, very good. I saw a bit of him on a western, Gunsmoke or something, not enough to have an opinion. I would like to see him playing other characters.
Was he type cast as was Jimmy Doohan?
He’s a DEM because he’s a godlike being brought in (the dictionary definition I used doesn’t specify it has to be at the end of the story) to explain why the universe is suddenly different. We’ve never seen him before and never will again, so we have only this one scene in this one story to convince us that he’s legitimately part of the universal order. Q, at least, was in it for a cheap laugh, which is an understandable motivation; the Guardian just says “I’m beyond your understanding, but I’m here to tell you something anyway.” This is inherently problematic.
Also: If he’s powerful enough to bend time and space, and it’s explicitly his job description to do so, why doesn’t he just scoop McCoy up and put him back where he belongs? Why does he require a pair of mortal agents to do this? “Why does God need a starship?” He’s the false note of an otherwise terrific story.
Nah. You’re using the term improperly.
The GOF is part of the set-up, not the resolution.
Gelflings can fly (at least the girls can.) Now that’s a DEM.
“You could have gone home any time you wanted.” DEM.
And, of course, “Don’t look, Marilyn!” Almost literally a Deus ex Machina! God emerges from a box!
ETA: Valid points in your next paragraph. Why couldn’t Kirk just ask the Guardian, “Wow! Can you fix what just went wrong?” But this gets into the realm of arguing with the premise. Maybe it violates the programming somehow.
Most guest aliens and deities on ST are never seen before their shows and never seen again after - though I believe the GOF is seen in one of the shows in the Animated Series. As for changing time, that did appear before - in the show “Tomorrow is Yesterday” where they didn’t want to return the pilot for fear of changing history then found that they had to because he would have a famous child.
If the Guardian, who has no apparent power to act, suddenly pulled McCoy away when all seemed lost, that would be a DEM. But that didn’t happen, did it?
“I was made to (show time, history?) in this fashion.” He explains that he can’t change events, merely show them at this speed.
<DEM Mode> Except in emergencies. </DEM Mode>
I’m just trying to show HH what the Guardian as a DEM looks like.
What emergency?