By the way, the Keystone XL project no longer includes the portion to Texas. It is from Hardisty, Alberta to Steele City, Nebraska.
The pipeline from Cushing, Oklahoma down to the Texas Gulf Coast is called the Gulf Coast Pipeline and is already under construction. Since it does not cross a national border it does not require State Department approval. It was dumb to combine the two separate section in one project approval in the first place. I think they wanted it to appear a more massive project to put pressure for approval. It backfired by delaying both instead of just the one.