  This note constructs the flat toric degeneration of the manifold FL_n of
flags in C^n from [Gonciulea-Lakshmibai 96] as an explicit GIT quotient of the
Gr"obner degeneration in [Knutson-Miller 03]. This implies that Schubert
varieties degenerate to reduced unions of toric varieties, associated to faces
indexed by rc-graphs (reduced pipe dreams) in the Gel'fand-Cetlin polytope. Our
explicit description of the toric degeneration of FL_n provides a simple
explanation of how Gel'fand-Cetlin decompositions for irreducible polynomial
representations of GL_n arise via geometric quantization.
