First it should be voluntary, in the case that it was a developed country, and more than that, that it had true, patriotic citizens (in many countries there are only territorial occupants), that way the love of the nation would be fostered. but it is very difficult to reach a level of culture where each individual is responsible for their actions, it becomes necessary to be service, to create a collective resposabulidad and a sertido of belonging to the land that saw it born.
But unfortunately these recruitment plans are applicable, only to low-class youth among other avitary measures.