  We present a self-consistent theory of magnetic short-range order based on a
spin-rotation-invariant slave-boson representation of the 2D t-J model. In the
functional-integral scheme, at the nearest-neighbour pair-approximation level,
the bosonized t-J Lagrangian is transformed to a classical Heisenberg model
with an effective (doping-dependent) exchange interaction which takes into
account the interrelation of ``itinerant'' and ``localized'' magnetic
behaviour. Evaluating the theory in the saddle-point approximation, we find a
suppression of antiferromagnetic and incommensurate spiral long-range-ordered
phases in the favour of a paramagnetic phase with pronounced antiferromagnetic
short-range correlations.
