  Multiply connected superconductors smaller than the coherence length show
destructive superconductivity, characterized by reentrant quantum phase
transitions driven by magnetic flux. We investigate the dependence of
destructive superconductivity on flux, transverse magnetic field, temperature,
and current in InAs nanowires with a surrounding epitaxial Al shell, finding
excellent agreement with mean-field theory across multiple reentrant
transitions. Near the crossover between destructive and nondestructive regimes,
an anomalous metal phase is observed with temperature-independent resistance,
controlled over two orders of magnitude by a millitesla-scale transverse
magnetic field.
