Require that any school which has a Zero Tolerance policy and also accepts funds from the Federal Government should have a review board evaluate the punishment students for "soft" violations. The board should include at least one counselor, one teacher, one administrator, and one member of law enforcement.
A "soft" violation would be acts committed without malice (bringing nail clippers to school, shaving one's head in a non-racially motivated act, etc.). The board would also have the ability to enact a permanent waiver for individual violations (all nail clipper violations waived, etc).
A "hard" violation would be acts committed with malice or where the act could result in harm or distuption to one or more students (firearms, drugs, etc.) and would not be covered by the review board.