One of the pillars of the charter school philosophy is at-will employment. This is why on both a national and state level, teacher unions oppose charter schools.
In private business, if someone hasn't performed his job satisfactorily he is asked to leave. This principle makes sense to pretty much everyone in the United States -- except those in public education.
Naturally, the success of at-will employment lies in people being reasonable and fair. An educator shouldn't be terminated the first time he makes a mistake. And there are two sides to the at-will employment agreement. A teacher can resign and leave a classroom without a prepared substitute.
About 45 school districts in Colorado have collective bargaining agreements with their teachers. Because charter school employees are employees of the charter school and not the school district, charter schools can use at-will agreements. This right to use only qualified, high-performing staff is central to why charter schools often outperform non-charter public schools. It's also a reason to vigorously oppose any actions that would require charter schools to, in any manner, submit to collective bargaining agreements.
Model at-will agreements for principals and teachers are online at http://www.cde.state.co.us/cdechart/guidebook/adm/pdf/JA_Admin_Contract.pdf and http://www.cde.state.co.us/cdechart/guidebook/adm/pdf/WWATeachingAgreement.pdf. Every charter school leader should examine their employment agreements, board policies and employee handbook to make sure nothing invalidates the at-will nature of employment at their school.