Create a 'Foreign Legion'

Create a foreign legion similar to the nations of France and Spain for overseas deployments to preserve the regular miltary for domestic defense. Applicants would be given the opportunity to gain citizenship after a duration of service (if they are a foreign national). This could lower defense costs by eliminating the need for private corporate contractors and preseve regular troops for essential service. Legionnaires would not be to rise above a certain rank, nor would they be able transfer service to the regular military and would based outside the country.