The proposed pipeline -- which would travel from Alberta's tar sands oil deposits to Gulf Coast refineries in the U.S. -- has drawn strong responses from individuals on both sides of a growing debate.
Supporters contend that the pipeline will create thousands of jobs and lower gas prices in the U.S. Opponents claim that the pipeline will carry oil which will contribute to climate change and a spill along the pipeline route could impact a large drinking and irrigation water source in Nebraska.
President Obama rejected TransCanada's permit for the Keystone XL in January, but his decision still leaves an opportunity for the company to reapply for permission to build the international pipeline.
In the first installment of our Change My Mind debate series, we challenge two leading voices in the debate to defend their views on the Keystone XL project.
Speaking against the Keystone XL is author and environmentalist Bill McKibben. He is the co-founder of 350.org and a leading voice in last year's Tar Sands Action protests against the Keystone XL.
His challenger is Canadian lawyer and author Ezra Levant. A columnist for Sun Media newspapers and a conservative commentator on the Sun News Network, Levant is also the author of 2010's "Ethical Oil: The Case for Canada's Oil Sands."
Join the debate below, and see if Bill or Ezra change your mind."