Star Wars has just revealed a disturbing weakness with lightsabers - one that, fortunately, the Empire never chose to exploit. When Obi-Wan Kenobi handed Luke Skywalker his father's lightsaber, he described it as "an elegant weapon for a more civilized time." Over the decades, the lightsaber has become the symbol not just of the Jedi, but of the Star Wars franchise itself.
Lucasfilm's Star Wars: The High Republic transmedia initiative explores the more civilized time Kenobi spoke of. These stories are set some 200 years before the events of Star Wars: Episode I - The Phantom Menace, at a time when both the Jedi Order and the Republic were at their height. This was long before the Jedi retreated into the Jedi Temple on Coruscant, foolishly cutting themselves off from ordinary people, becoming so afraid of the dark their light ceased to shine in the darkness. But it was also a time of great danger, because an expanding Republic found itself confronting terrifying new threats - a destructive pirate group called the Nihil, and a malevolent race known as the Drengir, ancient allies of the Sith. These threats coalesce in Cavan Scott's novel The Rising Storm, in which the Jedi learn of a weakness they were previously unaware of - one that can sabotage their very lightsabers.
One of the book's numerous sub-plots introduces a scientist named Manteesa Chekkat who has developed what she calls a nullifier. This contains a recainium core, illegal in the Republic, and upon activation it floods a circle 10 meters in diameter with radiation that disrupts any energy weapon - from the humble blaster to the sacred tool of the Jedi. The prototype is bulky, but Manteesa envisions creating much smaller devices that can be planted on ceilings inconspicuously, rendering Jedi unable to use their blades in the area around them.
As powerful as lightsabers may be, Star Wars has carefully established limits for them; some materials are lightsaber-resistant, most notably the Mandalorians' beskar. But this new twist is a particularly surprising limitation, in that it means it is possible to create areas where lightsabers simply don't work. Fortunately for the Jedi, this idea seems to have been relegated to the history books, likely because recainium radiation is damaging to organics and disrupts more than just lightsabers. The Separatists must never have figured this out, because it's easy to imagine them arming some of their droids with projectile weapons and setting up traps for Jedi where their lightsabers would be unexpectedly extinguished and the droids would open fire.
The Empire never seem to have developed recainium nullifiers either. They wouldn't have cared about the harmful effect of recainium radiation on their Stormtroopers, but the more generally disruptive effect of the nullifiers would have meant they were considered clumsy and ineffective. Besides which, by the time of the original trilogy the Jedi were believed to have been wiped out, and there have been hints the Empire even stopped looking for Jedi. By then, there would have been no point bothering with installing nullifiers and training troops to operate in areas where their energy weapons were disrupted. So it makes sense this particular lightsaber weakness was never exploited in the main Star Wars saga.
