  Superconformal Ward identities are derived for the the four point functions
of chiral primary BPS operators for $\N=2,4$ superconformal symmetry in four
dimensions. Manipulations of arbitrary tensorial fields are simplified by
introducing a null vector so that the four point functions depend on two
internal $R$-symmetry invariants as well as two conformal invariants. The
solutions of these identities are interpreted in terms of the operator product
expansion and are shown to accommodate long supermultiplets with free scale
dimensions and also short and semi-short multiplets with protected dimensions.
The decomposition into $R$-symmetry representations is achieved by an expansion
in terms of two variable harmonic polynomials which can be expressed also in
terms of Legendre polynomials. Crossing symmetry conditions on the four point
functions are also discussed.
