A two-week civil disobedience campaign against the controversial Alberta-to-Texas oil pipeline ended Saturday amid uncertainty over whether U.S. President Barack Obama will allow the project to go ahead.

Protesters held a final rally outside the White House after two weeks of daily sit-ins where roughly 1,250 people were arrested.

Organizer Bill McKibben, a well-known environmentalist and author, said the demonstrations have helped raise awareness about the environmental impact of the proposed project and Alberta's oilsands.

The big question now is whether the Obama administration will decide to block the pipeline, McKibben said.

"Canada's putting on full diplomatic pressure, and the oil companies have more money than god, but we've changed the odds a little bit these last two weeks," he said Saturday.

On Saturday, Natural Resources Minister Joe Oliver told CBC News he was "increasingly positive" the Calgary-based TransCanada Corp.'s proposed Keystone XL oil pipeline would get the green light from the Obama administration.

Oliver insisted the pipeline would have a "degree of safety greater than" the typical domestic pipeline system and would benefit the U.S. and Canadian economies by creating jobs and securing a domestic source of oil.

The U.S. State Department released its final environmental assessment in August of the $7-billion pipeline, determining the project would cause minimal risk. Energy Secretary Steven Chu also suggested this week that the pipeline was likely to get approved due to Canada's close ties with the United States.

In an interview Saturday, Oliver stressed the 2½-year study of the environmental impact of the pipeline concluded there would be no significant effect on most resources along the proposed project’s corridor.

But opponents say the pipeline – which would carry oilsands crude through six U.S. states to refineries in Texas – endangers a major source of water to millions of people.

Bill Erasmus, the Assembly of First Nations regional chief for the Northwest Territories who is in Washington D.C. supporting the protest, said the pipeline goes through the Ogallala Aquifer, which covers 450,000 square kilometres and includes portions of Nebraska, South Dakota, Wyoming, Kansas, Colorado, Oklahoma, New Mexico and Texas.

"If there is a spill in that aquifer, it will mess up the water for about four million people," Erasmus told CBC News on Saturday.  "The governor of Nebraska this week announced his opposition [because of that]."

Erasmus also dismissed claims the oil pipeline is critical for national security.

"This oil is going to be transported to the Gulf of Mexico; it is not for U.S. consumption," Erasmus said. "It’s for the highest bidder, it’s for the open market."

Klein among arrested

Erasmus said the oilsands continue to have a harmful effect on many indigenous communities in Alberta and Northern Canada.

"We’re finding drastic levels of low waters in our area," Erasmus said. "We're also finding the waters are being polluted from the massive tailings ponds that are at the tar sands and people in places like Fort Chippewa can no longer eat their fish. They can’t drink the water."

More than 1,000 peaceful protesters have been arrested by U.S. Park Police at the White House demonstration in the past two weeks and escorted to police vans in the past two weeks.

Canadian author Naomi Klein and aboriginal activist Gitz Deranger were among dozens arrested on Friday in front of the White House. Actors Daryl Hannah and Margot Kidder were also arrested during the two-week campaign.

Protesters said they plan to be back in October, while Erasmus told CBC News a big protest is in the works for Ottawa on Sept. 26.

Former U.S. vice-president Al Gore, now a leading environmentalist, has also weighed in.

In a plea to Obama earlier this week, Gore urged the president to block the pipeline, calling the oilsands "the dirtiest fuel on the planet."

The Obama administration has said it will make a final decision on the pipeline by the end of the year, after it determines whether the project is in the U.S. national interest.