The Empire
The Empire is a lot like a soda company. They've come out with many different flavors of evil, and while they all seem popular across the galaxy, they really aren't good for anybody. Their more popular flavors of evil include: murder, coercion, torture, more murder, genocide, regicide, jingoism, political strong-arming, extrajudicial sentencing, still more murder, and censorship. Did you notice any news networks in the film? Exactly.
Lucas doesn't mince with characterization in Star Wars. You won't find a scene where Grand Moff Tarkin wonders if he's doing the right thing, and it isn't until the sequels that we witness a side of Darth Vader that isn't a coldblooded killing machine. The Imperials are bad guys in the purest, most Saturday morning cartoon sense of the word.
While it is obvious that the Empire represents evil, it can be less obvious what the Star Wars universe specifically considers evil. What real world ideas and events are symbolized to the tune of the Imperial marching song?
Establishing Evil
We receive our first clue regarding the Empire's brand of evil in the film's establishing shot. As the shot pans down over Tatooine, we see a Rebel cruiser fly overhead, immediately followed by an Imperial star destroyer. The differences between the ships are immense, and this shot tells us everything we need to know about the Empire.
The Imperial ship is much larger than the cruiser, so it takes longer to pass by, its presence dominating the screen as it does so. We feel the power and the size of the Empire wrapped up in the imagery of the ship.
Before we meet the characters or the dialogue catches us up on current events, we already know everything we need to. The Empire's power and size prevails over the Rebels just as their ship prevails over the shot.
As the story progresses, we see how that power and size becomes a source of fear throughout the galaxy. The Empire uses both to make people obey and, like the cruiser, it destroys those who resist. As Grand Moff Tarkin says,
"The regional governors now have direct control over their territories. Fear will keep the local systems in line—fear of this battle station."
It's not just the Death Star they need to fear, though. It's the Empire itself that has its hands on the Death Star's trigger, and it is there that the fear is properly placed.
Space Nazis
Wait a second: an oppressive regime supported by a military complex that uses power and fear to force people to follow them… while killing any who resist. Doesn't that sound familiar?
Oh yeah, the Imperials are Space Nazis, or more to the point, space fascists.
The imagery of the Empire clues us into this one. The marches of the stormtroopers remind one of the Nazi propaganda film Triumph of the Will . Also,as Cole Horton points out, the design of the Imperial officer's uniforms was based on Prussian and German military uniforms from the Nazi era.
Darth Vader also serves as a type of Imperial Gestapo, or Nazi secret police. After capturing Princess Leia, Vader and an Imperial officer have the following exchange:
OFFICER: Holding her is dangerous. If word of this gets out, it could generate sympathy for the rebellion in the senate.
VADER: I've traced the rebel spies to her. Now she is my only link to finding their secret base.
OFFICER: She'll die before she'll tell you anything.
VADER: Leave that to me. Send a distress signal and then inform the senate that all aboard were killed.
Several unspoken implications here point to Vader's Gestapo-like qualities. The first is that Vader's capture of Princess Leia and her ship isn't strictly legal. If word reaches the senate, it will cause problems, which suggests this isn't part of the normal operations of the law. Indeed, Vader creates a cover story to hide his activities. Vader also implies that he's a-okay with killing Princess Leia if it leads to that. His justification for his actions is that Princess Leia is a traitor to the Empire for siding with the Rebels.
Given this, consider what the Jewish Virtual Library has to say about the Gestapo:
On April 26, 1933, Hermann Göring became the commander of this new force that was given power to shadow, arrest, interrogate, and intern any "enemies" of the state."
You can certainly draw parallels here with Vader.
The Gestapo also took part in the Third Reich's "Final Solution," the Nazi plan to extermination the Jews. While nothing so dark ever graphically appears in Star Wars, the destruction of Alderaan certainly has genocidal undertones to it, and certainly Vader had his hand in that.
In addition, the Empire is also anti-democratic. In a side comment, Grand Moff Tarkin points this out during his meeting with the Imperial commanders:
GRAND MOFF TARKIN: The Imperial Senate will no longer be of any concern to us. I have just received word that the Emperor has dissolved the council permanently. The last remnants of the old Republic have been swept away.
IMPERIAL COMMANDER: That's impossible. How will the emperor maintain control without the bureaucracy?
TARKIN: The regional governors now have direct control over their territories. Fear will keep the local systems in line—fear of this battle station.
The Empire has opted for a much easier, if seriously less fair, form of government: do as we say or we will blow you up. Hardly seems in keeping with the democratic ideals of freedom of speech, elected representation, and governmental restraint, now does it?
Product of the Times
The Empire symbolizes evil, but the ideas and imagery used to construct that evil stems from the nationalistic and fascist governments of Western society during the first half of the 20th Century—with the Nazis being the most obvious source of inspiration.
However, we've had a lot of evil empires, ruled by a lot of evil guys, in history. Why draw from this source specifically? A lot of reasons perhaps, but one we found fascinating claimed the decade Star Wars was made is responsible for the Nazi parallels found in Star Wars.
In 1977, America was still enmeshed in the Cold War. Fifteen years before, the Cuban Missile Crisis had brought the world as close to nuclear destruction as it likely has ever been. The Vietnam War had only ended two years before, too, and the war brought social turmoil in the form of a culture questioning the morality of the war. In response, the films of the 1970's tended to be super-gritty, and super-pessimistic.
The Empire harkens back to a time when the evils of the world were easier to understand—or, at least, when America was solidly on the side of 100% right. By drawing on the villains of the first-half of the 20th Century, Star Wars makes it easy to root for the heroes and desire to see the villains defeated.
Using this imagery to create the Empire, Star Wars creates a world lacking moral ambiguity. Who wants to see the Nazis win? No one. It is safe to assume the same goes for Space Nazis, a.k.a. the Empire, too.