Washington - Ranchers from Nebraska, people in car caravans from California and hundreds of others plan to hold daily sit-ins at the White House starting Saturday, protesting against a planned pipeline that would greatly expand the flow of oil from the black sands of western Canada.
Two weeks of protests will raise the question of what the United States should do about climate change, putting the topic back into the spotlight. They'll pressure President Barack Obama, who must decide whether the pipeline is in the national interest and whether it will be built.
For some participants, the key issues are local matters of land and water conservation. The proposed Keystone XL pipeline from the oil sands of Alberta would run from Canada through Montana, South Dakota, Nebraska, Kansas, Oklahoma and Texas.
It would cross the Ogallala Aquifer, the giant underground water source under much of Nebraska and other Great Plains states. Some Nebraskans have been calling for a different route away from their irrigation source and the state's Sand Hills, a land of canyons and mountains of grass-covered sand where cattle graze.
For others, the key issue is climate change.
Writer and protest organizer Bill McKibben says it may be the "single clearest decision Obama will make in his first four years because for once he has a clear shot. Congress isn't in the way. He gets to make the call."
McKibben said it's a test to see if Obama stands by his 2008 campaign promise that in his presidency "the rise of the oceans will begin to slow and the planet begin to heal."
An Obama denial of the permit for Keystone XL would "send an electrifying jolt through his base," McKibben said. "We'll be reminded about why we were so enthused when he was running."
The decision puts the president between his environmentalist supporters and those looking for projects that create jobs immediately. The American Petroleum Institute said the pipeline would create 20,000 direct jobs in the two years it would take to build it.
An existing Keystone pipeline from Canada already brings 591,000 barrels of diluted bitumen, the technical name for the thick oil mixed in the sands, to refineries in Oklahoma and Illinois. The new pipeline would increase the capacity to 1.3 million barrels a day and deliver the crude to refineries on the Gulf Coast.
Protesters argue that the pipeline would be in place for some 50 years, bringing a heavily polluting form of oil. The extra energy needed to mine the oil from the sands of Alberta and to process it creates more greenhouse gas emissions than conventional oil.
NASA climate scientist James Hansen argues that if emissions from coal are phased out in a few decades and unconventional fossil fuels such as the crude from the oil sands are left in the ground, it will be possible to stabilize the climate.
"Phase-out of emissions from coal is itself an enormous challenge. However, if the tar sands are thrown into the mix, it is essentially game over," Hansen wrote in a paper in June. Hansen in recent years has participated in protests, and organizers say he'll join this one as well.
The organizers said they expect some arrests. They plan to station people in Lafayette Park across from the White House every day for two weeks.
That means they'll be there in a week, when the president and his family return from their vacation on Martha's Vineyard.