Still, you don't want to bet your life that the assailant doesn't know how to wield a knife. I don't agree with shooting anyone who is brandishing a knife, but

Still, you don't want to bet your life that the assailant doesn't know how to wield a knife. I don't agree with shooting anyone who is brandishing a knife, but trying to disarm them is a horrible idea as well. As others have mentioned, using beanbag guns or a taser or tear gas or rubber bullets or just about any less-lethal option (with other officers ready to shoot if the assailant charges) is the best solution.