Students should be suspended for 30 days or longer if they deserve it. If they repeatedly keep making bad decisions then they should be kicked out for a long period of time. School is for learning not for getting in trouble all the time. If you are causing trouble every day then you should be kicked out for a while.
I think that schools have the right to suspend students for a month DEPENDING on the offense. If the offense is not severe than why suspend them for that long. Some people say that the suspension may impair their educational needs but if the student cared about his education he would not have engaged in the offense in the first place. Suspension for a month is necessary in some instances.
Losing a month of education can set a student so far back academically that is can take years to catch up, many of the types of students who are suspended are the ones that need that education time the most.
Parents need to work and are unable to supervise kids for such a long time which often means suspended students are out on the streets breaking the law.