Joe Biden and Elaine Cooper

Sierra ClubSierra Club activist Elaine Cooper with Joe Biden.

Vice President Joe Biden told an activist on Friday that he doesn’t support the proposed Keystone XL pipeline, according to a post on the Sierra Club website.

While the veep was working the crowd at an event in South Carolina, Elaine Cooper got a moment with him:

I asked him about the administration’s commitment to making progress on climate and whether the president would reject the pipeline. He looked at the Sierra Club hat on my head, and he said “yes, I do — I share your views — but I am in the minority,” and he smiled. …

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I know that this vice president is a man who isn’t afraid to speak from his heart, and who sometimes gets out in front of the rest of the administration on moral issues. It was nearly a year before, on May 6, 2012, that Biden said that he was “absolutely comfortable” with marriage equality. What the vice president said to me on Friday was equally brave and equally right.

Environmental leaders seized on the news, BuzzFeed reports:

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[Friends of the Earth President Erich] Pica released a statement commending the vice president for “his blunt talk”; and Gene Karpinski, president of the League of Conservation Voters, issued a press release calling the remarks “a big deal” and a “game changer that should encourage Secretary Kerry and President Obama to reject the Keystone XL tar sands pipeline.”

But did Biden really mean it? More from BuzzFeed:

Biden’s public position on the pipeline has been more reticent. Asked last year about Keystone, he deferred to the State Department’s ongoing review. “It’s going to go through the process and it will be made on an environmentally sound basis,” Biden said at the time.

What’s more, the vice president’s office told BuzzFeed Tuesday night that Biden’s views “haven’t changed” on the pipeline. “Any impression to the contrary would be mistaken,” an official said.

But activists cast the incident in South Carolina as a moment of candor from the often loose-lipped vice president. “I felt it was sincere at the time,” said Cooper.

The anti-Keystone “All Risk No Reward” coalition has already put together an ad referencing the incident, which will run on Beltway news site Politico, The Washington Post reports.

[The ad] first show[s] images of the recent oil spill in Arkansas, and then Biden and Secretary of State John Kerry holding hands as they confer.

“Psst … You should oppose Keystone XL too,” the ad reads. “Tell President Obama and Secretary Kerry: Joe Biden is Right.”

Biden seems to be laying the groundwork for a 2016 presidential campaign, so he might be more eager to please green voters than the rest of the administration.