Several thousand protesters from across the country encircled the White House on Sunday to demand that President Obama deny a permit for a proposed oil pipeline that would stretch from Alberta to the Texas coast.

Chanting “Hey, Obama, we don’t want your pipeline drama” and “yes, we can, stop the pipeline,” demonstrators warned the president that he won’t be able to rely on their support in the 2012 election if the TransCanada pipeline gains administration approval.

“It’s an issue that goes beyond politics. It’s a humanitarian issue,” said Quinten Anderson, 21, of Bloomington, Ind., who carried a sign that read “What would Sasha and Malia say.”

The State Department had been expected to decide by Dec. 31 whether the proposed pipeline may proceed, but in recent weeks there has been speculation that the decision could be delayed as the administration weighs economic and political implications.

After hundreds of protesters were arrested at a two-week sit-in at the White House in August, environmentalists have been stepping up efforts to influence Obama’s decision. They fear the pipeline would increase the reliance on fossil fuels and pose a danger to the environment should it leak.

The protesters, most wearing orange work vests, formed a chain that began at Lafayette Square and stretched south on 15th Street, across the Ellipse, and north on 17th Street next to the Old Executive Office Building.

Representatives of Tar Sands Action, which organized the protest, said it was the first time since the 1960s that a human chain had been formed around the White House. “The joke is we are trying to give [Obama] a great big hug, but it’s a show of solidarity to help him make the right decision,” said Linda ­Capato, a group organizer.

Before the demonstration, Maryland Del. Heather R. Mizeur (Montgomery), who is also a member of the Democratic National Committee, told the protesters that they represent Obama’s “base.”

“My role at the DNC is to support President Obama and all his endeavors,” Mizeur said. “But this year, I say it’s time to support us.”

After the protest, about 1,000 people joined Occupy DC in an impromptu, boisterous 90-minute march through downtown.