This is an important question. The origins of the "tough movement" comes from the 1970, but it is still important today. And as far as I can see, it will continue to be important in the future. This movement at root seeks to protect citizens from young offenders of the law, especially youth who are repeat offenders and who break the law through violence. The proponents of this position want to emphasize mandatory punishment and accountability. They feel that youth got away with too much and that things like rehibilitation and treatment must not take center stage. Of course, these are important, but cannot replace just punishment.
Part of the strategy is to deter youth from crimes. They want to stem crimes when they are smaller. From a larger perspective, we can say that the "tough movement" is a reform movement to deal with juvenile offenders of the law with the hopes of creating a just society.