Teacher tenure protects bad teachers from being fired for under performance. In any other industry in the United States, work performance is held to a standard and if you are unable to perform and get results, then often times you find yourself looking for another job. However when you are a teacher on tenure, you can work as long as you like with benefits and this isn't right in the education model of today.
It seems like all teachers are concerned about anymore is getting tenure. Then once they have it, they stop putting effort into their courses and into their students. I see this happening everywhere, and our children's education is suffering because of it. I think tenure has become something negative that is really impacting the entire education system.
Tenure is just another obstacle to firing bad teachers. No other profession has such a system, and teaching shouldn't either. However, to think getting rid of tenure means we can start firing all the bad teachers is naive. The teacher's union is still very powerful and will continue to be a force to be reckoned with.
I think teacher tenure is having an overall positive impact on the U.S. education system. I think the attainment of tenure makes new teachers do a better job in order to stay employed and one day get tenure. Tenure produces higher quality teachers who have a vested interest in educating kids.