  The star commutator of $:\phi(x) \star \phi(x):$ with $:\phi(y) \star
\phi(y):$ fails to vanish at equal times and thus also fails to obey
microcausality at spacelike separation even for the case in which
$\theta^{0i}=0$. The failure to obey microcausality for this sample observable
implies that this form of noncommutative field theory fails to obey
microcausality in general. This result also holds for general fields and
observables. We discuss possible responses to this problem.
