No. A million times no. And I hate the comparison, usually made by someone who may have seen Star Wars, but doesn't understand it/hasn't read any of the EU novels nor understands Palpatine/Sidous' motivations. Here are the biggest differences:
Sidious, on the one hand, betrayed and murdered his Master, Darth Plagueis. Sidious didn't care about money, he wasn't greedy, and he was well beyond asshole by the time most were first introduced to him in The Phantom Menace. He was so consumed with power, and the lust for more power, that it absolutely corrupted him. He was evil beyond reason. He actually convinced Darth Vader to kill his own son. THAT is Darth Sidious. . Dick Cheney is a greedy asshole, but he doesn't have the balls to go that far, which is why the comparison fails.
Dick Cheney is just a greedy asshole, nothing more. He's not evil,
just a greedy asshole. Cheney didn't, and wouldn't murder Bush to become
President. Darth Sidious would convince Congress to elect him Dictator,
then murder Bush, then have everyone in Congress killed, along with all 9
Supreme Court Justices.
If you think you have to attach Cheney to the Sith, or make him Sith like, just don't ok?
Comparison to Darth Vader: A MILLION TIMES NO!!!
Darth Vader fell to the Dark Side because he loved Padme so much, he would do anything for her, including betraying the Jedi Order. He wasn't evil. He was tempted to turn to the Dark Side, because he thought he could save Padme. After he turned, he flew into a rage because Padme died. He fed on that rage, which made him even more full of rage.
Dick Cheney loves money. And himself. And war, not because he likes killing, or others killing for him; but because he loves money. He isn't evil either, just a greedy bastard.
GRRRR... People, read the books!!