Robert Kennedy Jr., Connor Kennedy, actress Daryl Hannah and dozens of other civil rights activists were arrested on Wednesday during a climate change rally in Washington. The protest, which saw the high-profile activists attach themselves to the White House gates, was against the Keystone XL oil pipeline.

Police detained 48 protestors, including civil rights leader Julian Bond, Sierra Club President Allison Chin and Executive Director Michael Brune. The protest marked the first officially sanctioned act of civil disobedience allowed in the Sierra Club’s 120-year history.

The activists attached themselves to the gates with plastic zip ties and refused to move before officers made them. Protesters included ranchers, farmers and Native Americans, from along the pipeline route.

According to an emailed statement obtained by Politico, Kennedy said he was participating because he believes there are better sources of energy than the Canadian oil sands, a mixture of sand, water, clay and bitumen. He didn't elaborate on which alternatives he considers better options.

“This is the dirtiest possible source and most expensive for the energy consumer and for future generations who will have to pay the price,” Kennedy, an environmentalist who works with the Waterkeeper Alliance and the Natural Resources Defense Council, said in the email. “This is a boondoggle. It’s a giant criminal enterprise that has subverted democracy and will enrich a few billionaires and impoverish all of humanity by threatening civilization as we know it.”

Despite President Obama staying close-lipped on the subject of the pipeline, neglecting to even mention it in his State of the Union address Tuesday evening, he did speak extensively about the responsibility to do more to combat global warming.

Protesters wearing “No KXL” buttons chanted, “Hey, Obama, we don’t want no climate drama,” and “Barack Obama, yes you can stop the dirty pipeline plan” as they watched the other activists being arrested. Obama was in North Carolina at the time of the protest.

While the pipeline proposal is being reviewed by the State Department, many of the activists have returned to Washington to participate in Sunday’s Presidents Day weekend rally.

Activists from the Sierra Club, and the Hip Hop Caucus, among others, plan to march from the Washington Monument to the White House. That rally is projected to bring 30,000 people to the area, organizers have said.