So, you contend that government has an inherent responsibility to provide publicly-governed education, and you refute the government position that it merely has to provide education to the public?
If that is so, and the government has not yet privatized and seeks to garner support, then you might try validate:
demonstrate or support the truth or value of
The government is trying to validate its attempts for privatization of the educational system [by expounding on the lower cost to citizens, etc.]
If the government has already privatized, and is giving reasons why they decided such, then consider justify: