  We provide a new proof of James' sup theorem for (non necessarily separable)
Banach spaces. One of the ingredients is the following generalization of a
theorem of Hagler and Johnson (1977) : "If a normed space $E$ does not contain
any asymptotically isometric copy of $\ell^1(\IN)$, then every bounded sequence
of $E'$ has a normalized block sequence pointwise converging to 0".
