I don’t think Tarkin has to be a Sith - more that he’s a smart cookie and knows how the politics work. He knows that if he could find some way to take down Vader, it would make him look more powerful/valuable in Palpatine’s eyes.
But tarkin isn’t force sensitive. He may be able to kill Vader through political manipulation or something, but he could simply never beat him in a fight. And that’s kindve important for rule of 2.
I don’t think Tarkin has to be a Sith - more that he’s a smart cookie and knows how the politics work. He knows that if he could find some way to take down Vader, it would make him look more powerful/valuable in Palpatine’s eyes.
But tarkin isn’t force sensitive. He may be able to kill Vader through political manipulation or something, but he could simply never beat him in a fight. And that’s kindve important for rule of 2.