SEPTEMBER 2008
TransCanada applies to extend its existing Keystone pipeline, beginning a long permit process at the state and federal levels. The new section would be dubbed Keystone XL.
APRIL 2010
BP’s Deepwater Horizon oil-drilling unit explodes, spilling more than 200 million gallons of crude oil into the Gulf of Mexico and bringing attention to the risks of oil projects.
NOVEMBER 2011
President Obama postpones a decision on Keystone XL until after the 2012 election in the face of stiff opposition from environmental activists and landowners.
JUNE 2013
Obama says that to receive his approval, the new pipeline could not contribute significant levels of new carbon pollution. Activists would later remind Obama of this statement.
DECEMBER 2014
Energy Transfer Partners applies to the federal government, with little fanfare, to build the Dakota Access pipeline.
NOVEMBER 2015
Obama rejects Keystone XL, citing the negative publicity associated with the project and upcoming negotiations for a global climate deal. The move comes despite a request from TransCanada to suspend the application.
DECEMBER 2016
The Army declines to allow Energy Transfer Partners to build under the Missouri River and soon begins a review of the project that could take two years.
OCTOBER–NOVEMBER 2016
Resistance to DAPL grows as law enforcement uses dogs, water cannons and tear gas to remove protesters. Nationally, millions post to Facebook in solidarity.
JULY 2016
The Army Corps of Engineers issues permits for Dakota Access to cross the Missouri River, near the Standing Rock lands, without a full impact assessment.
APRIL 2016
Dakota Access opponents gather at the planned construction site, arguing the pipeline would disrupt ancient burial grounds near the Standing Rock Indian Reservation and threaten the clean-water supply. More protesters join them.
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Write to Justin Worland at justin.worland@time.com