Macroscopic character of composite high temperature superconducting wires

The ``d-wave'' symmetry of the superconducting order in the cuprate high temperature superconductors is a well established fact, and one which identifies them as ``unconventional.'' However, in macroscopic contexts -- including many potential applications ({\it i.e.} superconducting ``wires'') -- the material is a composite of randomly oriented superconducting grains in a metallic matrix, in which Josephson coupling between grains mediates the onset of long-range phase coherence. Here, we analyze the physics at length scales large compared to the size of such grains, and in particular the macroscopic character of the long-range order that emerges. While XY-superconducting glass order and macroscopic d-wave superconductivity may be possible, we show that under many circumstances -- especially when the d-wave superconducting grains are embedded in a metallic matrix -- the most likely order has global s-wave symmetry.