The Keystone-Cushing extension (Phase II), running away480-kilometre (300 mi) from Steele City to storage and distribution facilities (tank farm) at Cushing, Oklahoma, completed in February 2011.
The Gulf Coast Extension (Phase III), running 784-kilometre (487 mi) from Cushing to refineries at Port Arthur, Texas was completed in January 2014, and a lateral pipeline to refineries at Houston, Texas and a terminal will be completed in mid-2015.
It is only the Phase IV leg, running from between Hardisty, Alberta, and Steele City, Nebraska that wasn't approved. That part crosses the U.S.-Canadian border.
Obama signed off on the rest (symbolically, I believe, as I don't think it required Federal approval), back in 2011.