When Palpatine rose to power and declared himself Emperor, Tarkin was a governor of the Seswenna Sector. He supported Palpatine throughout, and when he introduced the 'Tarkin doctrine', he was the first to be elevated to the rank of 'Grand Moff'. It was Tarkin who came up with the idea of ruling by fear, as he once said : 'Rule through the fear of force, rather than the force itself.'
Tarkin was a tall, thin man. He had gaunt features which made him seemed ruthless, which in fact he was. He was always respected and feared throughout the ranks of the Navy. After he became Grand Moff, Tarkin set up a secret installation in the Maw cluster. It was here that he developed the plans for perhaps the most infamous weapon in the galaxy, the Death Star. Tarkin knew that this weapon would strike absolute fear into everyone who saw it, or even heard its name. The Death Star was his dream, and when Palpatine saw the plans for it, he approved the project immediately.
Tarkin thought the Death Star was invincible, vulnerable perhaps only to the largest of ships. But he thought twice when the plans were stolen by Rebel spies, who were attempting to assassinate Tarkin. With plans gone, there was always the chance that a vulnerable spot might be found. This gnawed at Tarkin, but it did not stop him from testing his brainchild. The Death Star had been constructed over the planet Horuz, an Imperial penal colony. Tarkin ordered the planet destroyed, firstly to test the weapon, and secondly to stop any of the construction workers from leaking information about the Death Star.
With the Death Star built, Tarkin realised just how much power was at his fingertips. He had over 1 million personnel to do his bidding, and the most powerful weapon in the galaxy. To aide him in his task, Palpatine sent over Darth Vader, and assigned Admiral Motti and General Tagge to Tarkin's staff. Motti despised Vader, and Tagge did not hide his contempt for Tarkin. Although Tarkin's main dream had been realised, he had had another. With the Death Star, he could depose the Emperor, and take his place. This dream he hid from everyone, except Vader, from whom no-one but Palpatine could anything. But Vader kept quiet about this. But Motti impressed upon Tarkin the fact that Palpatine would not be able to stop Tarkin from taking the reigns of the Empire.
Vader was sent off to search for the missing plans, leaving Tarkin to contemplate his next move against Palpatine. When Vader returned with Leia Organa, Tarkin had just received news that was music to his ears, Palpatine had just dissolved the Imperial Senate. He ordered Leia to be interrogated immediately, but when human interrogation did not work, interrogation droids were used. But Tarkin had underestimated Leia's strong will, and she did not allow herself to divulge the place where the plans had been taken, not even under extreme pain from the droids. Tarkin felt that there was only one other way to discover where the plans were, by threatening to destroy Alderaan, Leia's home planet. This pressure produced an answer from Leia, but Tarkin showed his utter ruthlessness by destroying Alderaan anyway. But once again he had underestimated Leia, She had lied when she said the plans were on Dantooine, and Tarkin found himself back at square one, with the Emperor breathing down his neck.
He had two choices : find the plans, destroy the Rebellion or overthrow Palpatine. Or he could forget about the rebels for now and go straight for the Imperial throne. His military conscience won over, and he decided to carry on the search. However, things got complicated when Obi-Wan Kenobi showed up with Han, Chewie and Luke. Tarkin was astonished to hear that not only was Obi-Wan alive, he was on the Death Star. He knew the danger that Kenobi presented, and allowed Vader to set off after him. Although Tarkin was a military genius and could find the weakness of armies in order to destroy them, he was no match for a Jedi Knight.
Tarkin was essentially a coward. He feared confrontations when he was unable to hide behind large weapons of destruction, or hundreds of troops ready to die for him. In battle, he would not be found on the battlefield fighting with his troops, giving them courage by his very presence; he would be far away, in a silken tent with a model of the battle in front of him. From there he would command, leaving the real dirty work to others. This is what the Empire was made up of : cowards. The only one who differed from this was Vader, who would stand alone in battle and fight hundreds of thousands of soldiers.
With Ben dead, and the rebels escaping with the princess, and without the knowledge of the rebel base, Tarkin had to use desperate measures and take an incredible gamble. He would allow the rebels to escape, using only a token force to try to stop them. He placed a homing beacon on board the Millenium Falcon, knowing the rebels would scurry away to their hidden base in an attempt to find the Death Star's weakness.
His gamble proved to be a good and bad one. Good because he was successful in finding the rebel base, but bad because it resulted in his dream, along with himself, being destroyed.
Tarkin's legacy lived on for years afterwards, in the second Death Star. This was again destroyed by the rebels.
This all proved that Tarkin's doctrine was wrong. One cannot rule by fear, as fear will only cause someone to turn that fear into a weapon. Tarkin was always doomed, as he underestimated his opponent time and again, not realising that the fear he spread would be used against him, and ultimately destroy him.
