A true Darth Jar Jar would have stayed in the Senate, taking Padme’s place as full Senator of Naboo, and acted as controlled opposition to the Emperor. He would act as a release valve for anyone opposing Imperial plans, especially non humans, and quietly deal with anyone he couldn’t control.

Mon Mothma and Bail Organa would have been neutralized in this case. He might have even stumbled onto Leia’s true identity.