That... Almost sounds like a sane, rational way to run an army. Provide an external motivation that doesn't include rabid parochialism and tie it to the wellbeing of the country.
Singapore has maintained an odd tradition, inherited from the British. They keep a regiment of Gurkhas around, professional soldiers from Nepal. They form an independent group within the Singapore Police, and are not allowed to form deep social connections within Singapore. This, in theory, keeps them a disinterested third party.
