The Jedi lost a lot of abilities they and the Sith previously had. For many years they had a semi peace. In these times without war people let their guard down and become over confident. Thousands of years ago in the Jedi-Sith war they used many lost or weakened abilities such as Inhanced battle meditation and such, I see very little of these powers used through the clone war times. Throughout the entire movies and various novels comics etc many powerful Jedi comment on their senses being clouded by the dark side. Like Master Yoda and Master Windu.

This was Sidious master play.... and he pulled it off to perfection. Using his position and hiding his abilities, he became senator and used the battle of Naboo to become head of the republic then started a war and this forced the Jedi out of their usual roles as peace keepers with their strength centered. Spread them throughout the entire galaxy. Throw numerous threats their way to keep them fighting and stuck leading armies of clones against a force of droids. Jedi are not omnipresent beings all knowing and all powerful. Sith since Darth Bane have followed the rule of two, this means fighting a force of thousands so obviously sith are going to be masters of deception hiding in sight and manipulation and this years long plan by the emperor was well planned well thought and hit their weaknesses dead on. The Jedi knew something was wrong but with the entire galaxy at war they had little chance to follow leads find the Sith. The Sith used the droid army to attack and oppress hundreds of worlds forcing the Jedi to defend these helpless people.

I love the movies and can't help but feel admiration for the Emperor...waiting years, playing a good guy, manipulating Anakin, gaining more power by using that fool Jar jar well Padme was forced into hiding by another part of the Emperor's plan. The details and strength to hold a plan for years and years. How could the Jedi possibly see this? They couldn't. Maybe if the majority of the Jedi were on Coruscant instead of spread so thin, they might have held off an attack on their base and been able to arrest or kill Palpatine and convince the senators of the treacherous plan. But long before order 66 they doomed themselves and if they hadn't acted to protect the other planets they couldn't really be the jedi as thats their job their role and creed. Going to war with clones created mysteriously by a long dead Jedi? Huge mistake. And many more followed but this was a huge one.

Sorry so long but I wanted to get the point out.