Increasing the Security in Schools

Every one is talking about the need to increase security in our schools.  Here is my proposal.  Every school should have one or two teachers designated as 'Security Officers.  These individuals would receive the same training as a reserve police officer.  They would have access to tactical weapons in a secure location in their classroom.  Every school would have the capability for locking the doors from the outside with one button.  In the event of a breach of security all of the classroom doors would be locked and the designated teachers would spring into action.

You may be asking how we would pay for these enhancements.  The teacher's unions are concerned with security.  They can take the money that they are currently wasting on campaign contributions and political lobbying and give it to the schools for enhanced security.  How would the money be best spent?