CALGARY - A San Francisco billionaire has challenged TransCanada boss Russ Girling to a live debate on the controversial Keystone XL oil pipeline.

Tom Steyer, an ardent critic of the project and a major Democratic financier, extended his invitation in an open letter to Girling on Tuesday.

"I care so much that the truth comes out that I hereby challenge you to a debate on the merits and faults of the Keystone XL pipeline," Steyer wrote.

"Let's have a real, substantial conversation about the issues at hand, and have the viewing public and have the public decide for themselves as to which of us is in possession of the more persuasive and the more important argument."

Earlier this year, Steyer teamed up with a coalition of environmental groups on an anti-pipeline social media campaign.

A TransCanada (TSX:TRP) spokesman didn't say if Girling would accept the challenge.

"We respect the environmental review process put in place by the U.S. Department of State and we have been working within that process for nearly five years," said Shawn Howard in an email.

"A decision on a Presidential Permit for Keystone XL will ultimately be made by the administration and we are hopeful that decision is made in the coming months."

Howard added the project is expected to create thousands of jobs and displace U.S. imports of crude from unfriendly countries — assertions Steyer disputes in his letter.

A draft State Department report earlier this year raised no major environmental red flags with the proposal, which had been rerouted to reduce some of the ecological impact in Nebraska.

U.S. President Barack Obama — who has final say over the pipeline — has expressed skepticism that the pipeline will be a significant job creator.

Also on HuffPost:

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  • <em>From Getty:</em> SAN FRANCISCO, CA - OCTOBER 25: Protestors against the construction of the Keystone XL oil pipeline hold signs and stand on a Keith Haring sculpture as they demonstrate outside of the W Hotel before the arrival of U.S. President Barack Obama on October 25, 2011 in San Francisco, California. Hundreds of protestors from a wide variety of activist groups staged protests outside of the W Hotel where President Obama was holding a $7,500 per person fundraiser. (Photo by Justin Sullivan/Getty Images)

  • <em>From Getty:</em> SAN FRANCISCO, CA - OCTOBER 25: A protestor against the construction of the Keystone XL oil pipeline climbs on a Keith Haring sculpture as he demonstrates outside of the W Hotel where U.S. President Barack Obama was holding a fundraiser on October 25, 2011 in San Francisco, California. Hundreds of protestors from a wide variety of activist groups staged protests outside of the W Hotel where President Obama was holding a $7,500 per person fundraiser. (Photo by Justin Sullivan/Getty Images)

  • <em>From Getty:</em> Demonstrators listen to speakers in Lafayette Park across from the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline. (Photo credit should read KAREN BLEIER/AFP/Getty Images)

  • <em>From Getty:</em> Demonstrators listen to speakers in Lafayette Park across from the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline. (Photo credit should read KAREN BLEIER/AFP/Getty Images)

  • <em>From Getty:</em> A demonstrator waves signs in Lafayette Park across from the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline.

  • <em>From Getty:</em> A demonstrator dressed as an oil soaked bird in Lafayette Park across from the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline.

  • <em>From Getty:</em> Demonstrators listen to speakers in Lafayette Park across from the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline.

  • <em>From Getty:</em> A demonstrator holds signs in front of the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline.

  • <em>From Getty:</em> A demonstrator holds a magazine open to an article concerning tanker routes for the proposed Keystone XL Pipeline in front of the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline.

  • <em>From Getty:</em> Children demonstrate in front of the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline. AFP PHOTO / Karen BLEIER

  • <em>From Getty:</em> Demonstrators hold up a banner in front of the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline. AFP PHOTO / Karen BLEIER

  • <em>From Getty:</em> Demonstrators begin to line up around the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline.

  • <em>From Getty:</em> Demonstrators in front of the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline.

  • <em>From Getty:</em> Demonstrators line up in front of the White House in Washington, DC November 6, 2011. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline.

  • <em>From Getty:</em> A sign is seen in Lafayette Park across from the White House in Washington, DC November 6, 2011 during a protest. Thousands of people are descending on the White House to join hands with one another and stand up to the Keystone XL pipeline.

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/6320235175/in/set-72157628079975942" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/6320925438/in/set-72157628079975942" target="_hplink">Emma Cassidy and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/6320975886/in/set-72157628079975942" target="_hplink">Shadia Fayne Wood and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/6320307073/in/set-72157628079975942" target="_hplink">Amy Dewan and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/6320919878/in/set-72157628079975942" target="_hplink">Emma Cassidy and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/6320760272/in/set-72157628079975942" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/6321050482/in/set-72157628079975942/" target="_hplink">Clayton Conn and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/mothernature/6306631974/" target="_hplink">mothernature photography</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>

  • <em>Flickr image courtesy of <a href="http://www.flickr.com/photos/tarsandsaction/" target="_hplink">Josh Lopez and Tar Sands Action</a>.</em>