  We introduce a novel decomposition of the four dimensional SU(2) gauge field.
This decomposition realizes explicitely a symmetry between electric and
magnetic variables, suggesting a duality picture between the corresponding
phases. It also indicates that at large distances the Yang-Mills theory
involves a three component unit vector field, a massive Lorentz vector field,
and a neutral scalar field that condenses which yields the mass scale. Our
results are consistent with the proposal that the physical spectrum of the
theory contains confining strings which are tied into stable knotted solitons.
