What happened?
In June 22, 2010 Rolling Stone magazine published an article in which McChrystal and his staff made disparaging remarks about US foreign policy about U.S. officials including Vice President J. Biden. Despite the fact that general McChrystal immediately apologized for the article, the scandalous publication reached the POTUS office. On June 2010, General McChrystal had to resign.
Why?
Civilian Control of the Military is Fundamental to American Democracy. The module of American democracy is built around the concept that civilians will always be in control of the military. Undermining the civilian control of the military is against the core values of American democratic system. (US Constitution - Article I,