U.S. President Barack Obama, flanked by Secretary of State John Kerry (right) and Vice President Joe Biden, announces the rejection of the proposed Keystone XL pipeline at the White House, Nov. 6, 2015. Mandel Ngan/AFP/Getty Images

U.S. President Barack Obama announced Friday that he has rejected the highly controversial Keystone XL pipeline, citing environmental concerns and saying the project "would not serve the interests of the United States." His announcement brings to an end the yearslong review and discussion of the pipeline, which had become a symbol of partisan debate over fossil fuels in recent years.

The president spoke at the White House Friday morning, flanked by Vice President Joe Biden and Secretary of State John Kerry, who gave Obama his recommendation to reject the pipeline earlier Friday.

“The pipeline would not make a meaningful long term contribution to our economy,’’ Obama said.

The State Department has been reviewing the project, which would have run crude oil 1,200 miles from Canada to the Gulf Coast, for the majority of Obama’s presidency, and the issue was a frequent topic of discussion in national elections. It often pitted energy advocates and Republicans, who said the pipeline would create jobs and ensure energy security, against environmental activists and liberals concerned about the effect Keystone XL would have on climate change.

The project had seen especially heightened attention in recent months, as environmental activists hoped Obama would reject the pipeline before United Nations climate talks take place in Paris this month. By rejecting the Keystone XL pipeline, Obama is likely to secure a favorable mark on his environmental legacy, but he also ensures that this issue will not go away quietly.

All three Democratic presidential candidates have said they oppose the pipeline, while Republican candidates support it and are unlikely to drop the issue as they continue campaigning in the 2016 election. Several Republican presidential candidates responded to the news on Twitter immediately following Obama’s announcement.

While a rejection from the White House does mean the project is dead for now, the pipeline's backers are expected to challenge his decision in court, according to the Associated Press. TransCanada, the company behind Keystone XL, requested a suspension of its federal permit Monday in what was widely seen as an attempt to avoid Obama's imminent rejection of the project. The White House said it would not suspend the application, however, and promised Obama would make a decision before the end of his term as president.

In addition to efforts by TransCanada, the Republican-controlled Congress could try to override the president, but similar efforts have failed in the past. Another option for the pipeline would be for TransCanada to reapply should a Republican win the White House and take over from Obama in 2017.

During his remarks Friday, Obama said he had informed Canadian Prime Minister Justin Trudeau of his decision regarding the pipeline and that he was confident the two governments would continue to work together on other issues. Trudeau has said he supports the building of Keystone XL, but he made it clear during his recent campaign that he wanted to take a more friendly approach to relations with the United States than his predecessor, Stephen Harper, who strongly pushed Obama to accept the pipeline. Obama seemed to indicate Friday that the U.S.-Canada relationship would not suffer due to his decision.

"This morning, I also had the opportunity to speak with Prime Minister Trudeau of Canada. And while he expressed his disappointment, given Canada’s position on this issue, we both agreed that our close friendship on a whole range of issues, including energy and climate change, should provide the basis for even closer coordination between our countries going forward," the president said.

Justin Trudeau | Graphiq

After Obama's remarks Friday, Trudeau issued his own statement echoing the president's sentiment of friendship and emphasizing his own country's commitment to fighting climate change.

"The application for a cross-border permit for the Keystone XL pipeline project was turned down by the United States Government today. We are disappointed by the decision but respect the right of the United States to make the decision," Trudeau said in the statement. "The Canada-U.S. relationship is much bigger than any one project and I look forward to a fresh start with President Obama to strengthen our remarkable ties in a spirit of friendship and cooperation."

The State Department, which reviews all international pipelines, released a statement Friday explaining its recommendation on the project and reiterating U.S. support for Canada.

“The critical factor in my determination was this: Moving forward with this project would significantly undermine our ability to continue leading the world in combating climate change,” Kerry said in the statement.

The statement also included a list of key findings that influenced Kerry’s decision:

  • The proposed project has a negligible impact on our energy security.

  • The proposed project would not lead to lower gas prices for American consumers.

  • The proposed project’s long-term contribution to our economy would be marginal.

  • The proposed project raises a range of concerns about the impact on local communities, water supplies, and cultural heritage sites.

  • The proposed project would facilitate transportation into our country of a particularly dirty source of fuel.

Given the focus on environmental issues from Obama and Kerry Friday, environmental activists rejoiced at the long-awaited announcement.

“This represents a courageous leap forward in the climate fight. Rejecting the Keystone XL tar sands pipeline is right for our nation, for our children and for our planet,” Rhea Suh, president of the Natural Resources Defense Council, said in a statement Friday. “It would have locked in, for a generation or more, massive development of among the dirtiest fuels on the planet – posing a serious threat to our air, land water, and climate. The proposal, pushed largely by the fossil fuel industry, was a recipe for disaster. In no way was the pipeline in America’s national interest.”

“Dangerous climate change is the central environmental challenge of our time, and it’s time for everyone to step up now and meet that challenge,” Suh added.