You have to follow issues arising in the approval of Transcanada’s Keystone XL pipeline closely to understand the latest delay.
Two plus years ago TransCanada realized it had to re-route the path of Keystone to avoid fundamental criticism from environmentalists,. The path originally chosen threatened the Oglala aquifer, a critical source of water in the dry American Midwest.
To expedite a new routing, TransCanada moved quickly, using all legal and commercial means at its disposal. Unfortunately certain Nebraska farmers were not prepared to be steamrollered. They took their case to court, arguing that the methods TransCanada used were improper. Late last fall the court delivered its verdict, siding with the farmers. TransCanada appealed this decision. Sometime later this year or next the Nebraska Court of Appeal will deliver its judgement.
In the meantime, the US State Department has extended the period for its administrative review. Until its final review is completed, President Obama will not decide whether Keystone should be approved.