In this Wired magazine article [HT: Instapundit], Spencer Ackerman gives a detailed critique of Darth Vader’s strategy at the Battle of Hoth. Presented with a golden opportunity to wipe out the rebels once and for all, Vader let them slip through his fingers:
How did the Galactic Empire ever cement its hold on the Star Wars Universe? The war machine built by Emperor Palpatine and run by Darth Vader is a spectacularly bad fighting force, as evidenced by all of the pieces of Death Star littering space. But of all the Empire’s failures, none is a more spectacular military fiasco than the Battle of Hoth at the beginning of The Empire Strikes Back.
From a military perspective, Hoth should have been a total debacle for the Rebel Alliance. Overconfident that they can evade Imperial surveillance, they hole up on unforgiving frigid terrain at the far end of the cosmos. Huddled into the lone Echo Base are all their major players: politically crucial Princess Leia; ace pilot Han Solo; and their game-changer, Luke Skywalker, who isn’t even a Jedi yet.
The defenses the Alliance constructed on Hoth could not be more favorable to Vader if the villain constructed them himself....
When Vader enters the Hoth System with the Imperial Fleet, he’s holding a winning hand. What follows next is a reminder of two military truths that apply in our own time and in our own galaxy: Don’t place unaccountable religious fanatics in wartime command, and never underestimate a hegemonic power’s ability to miscalculate against an insurgency.
Actually, Vader’s errors at Hoth are even worse than typical mistakes in counterinsurgency warfare. In this case, the insurgents were trapped, and forced to fight a conventional battle against a greatly superior force. Yet Vader still let them get away. In addition, it’s hard to understand why the imperial ground troops went in on clumsy snow walkers, which move at a snail’s pace and are highly vulnerable to air attack. Even World War II-era battle tanks were faster. And speed was clearly of the essence, as the storm troopers needed to occupy the rebel base before key insurgent leaders like Leia could escape. The Imperial troops could have taken the base faster by adopting the primitive WWII strategy of landing paratroopers on top of it (thereby outflanking the defending forces which were miles away waiting for the snow walkers) or even riding in on tauntauns. It’s almost as if Vader was just toying with the rebels so he could fight a more tactically interesting battle against them in the next movie!
In fairness, the Emperor and Vader were not always this incompetent. I offered a more positive appraisal of their leadership methods here.