Because of the gaps in the melody, as Andrew writes, and for other reasons of rhythm, the tune requires some accompaniment. However, in my ears a regularly strummed guitar has a lulling effect, counteracting the message of the lyrics. It would be even much worse if you omitted the bass.

If I were to arrange the song, I might try more harmony voices, human or instrumental, filling the gaps and hinting (not stomping) the basic beat. An a-cappella ensemble would be good, were it not for the problem of syllables distracting from the lyrics; thus we probably need some instruments. An oboe may convey some oriental colour and thus escape the girl scouts' camp feeling.