Two approaches to extend Hardy's proof of nonlocality without inequalities
to maximally entangled states of bipartite two-level systems are shown to f
ail. On one hand, it is shown that the proof of Wu and co-workers [Phys. Re
v. A 53, R1927 (1996)] uses an effective state which is not maximally entan
gled. On the other hand, it is demonstrated that Hardy's proof cannot be ge
neralized by the replacement of one of the four von Neumann measurements in
volved in the original proof by a generalized measurement to unambiguously
discriminate between nonorthogonal states.