WASHINGTON — A decision on whether to build a pipeline from Canada’s oil sands to Texas will be delayed, probably until 2013, to allow time to consider rerouting a section in Nebraska, the State Department announced Thursday.

The requirement for a new environmental impact statement and more public comments means the decision won’t be made until after the 2012 elections. Controversy over the pipeline created a headache for the Obama administration, but the delay might not end it.

Environmentalists have made the proposed Keystone XL pipeline a test case of whether President Obama will fight climate change. The pipeline would ensure decades of an increased supply of a form of oil that produces more heat-trapping emissions than conventional oil does because more energy is needed to extract and refine it. The State Department said the delay was about the impact on Nebraska, not climate change.