However , his departure from the service sharply reduced his ability to influence military policy and public opinion .
Mitchell resigned instead on February 1 , 1926 , and spent the next decade writing and preaching air power to all who would listen .
Mitchell 's departure from the service sharply reduced his ability to influence military policy and public opinion .
Mitchell resigned instead on February 1 , 1926 , and spent the next decade writing and preaching air power to all who would listen .