TransCanada Corp.'s proposed Keystone XL pipeline has become a litmus test in the U.S. battle over energy policy, as the environmental movement looks for reassurance that President Barack Obama is committed to combatting climate change.

 Prodded by congressional Republicans for a quick decision, the U.S. State Department concludes a comment period on Monday for its draft environmental impact statement on the XL project. 

 The final version - to be issued this summer - will likely conclude that the environmental concerns should not derail the project, despite troublesome leaks from the existing Keystone pipeline, which was shut last week after a small leak in Kansas.