  Let f be a newform of weight 2k-2 and level 1. In this paper we provide
evidence for the Bloch-Kato conjecture for modular forms. We demonstrate an
implication that under suitable hypothesis if a prime divides the algebraic
part of L(k,f), then the prime divides the order of the Selmer group associated
to f. We demonstrate this by establishing a congruence between the
Saito-Kurokawa lift of f and a cuspidal Siegel eigenform that is not a
Saito-Kurokawa lift. We then examine what this congruence says in terms of
Galois representations to produce a non-trivial p-torsion element in the Selmer
group.
