A high-profile U.S. senator has passionately defended TransCanada's Keystone XL pipeline and Alberta's oilsands, putting her at odds with some of her fellow congressional lawmakers.

Republican Lisa Murkowski, a senator from Alaska perhaps best-known for her legendary feuds with former governor Sarah Palin, said on Wednesday she was "stunned" at the opposition to Keystone XL given it would transport a much-needed source of energy to the United States from a trusted friend and trading partner.

In response to a question from the Canadian American Business Council, Alaska's Murkowski spoke at length on the approximately $7-billion project, and Alberta's oilsands, at a Women in Washington conference hosted by The Atlantic magazine.

"Canada is our neighbour, our friend, our best trading partner and happens to be sitting right there above us, able to transport a resource that we need," she told the high-powered crowd of lobbyists, diplomats and lawmakers past and present.

"You're not putting crude in a vessel and sending it across thousands of miles of water; you're putting it in a pipeline, the safest way to transport…If we're not going to produce [oil] here, I want to know that we're getting it from someone who likes us, who we like, and who has high environmental standards and is going to be there for the long haul with us."

Murkowski also defended the carbon-intensive methods used to extract oilsands crude. The American environmental movement is opposed to Keystone XL in large part because of the oilsands, and has urged the U.S. State Department to block the project to help put the boots to "dirty oil."

"People don't like mining, people don't like extraction, but it is our reality," she said.

"So let's figure out how we do it safely, how we do it responsibly, and let's work on perfecting that. We're going to need to continue to dig holes. It's just what has to happen."

Canada is not going to shut down the oilsands if the U.S. blocks the pipeline, she added.

in-220-lisa-rtr2fwvx

Republican Lisa Murkowski's said Wednesday she was stunned at the opposition considering the pipeline would transport a much-needed source of energy to the United States. (Larry Downing/Reuters)

"We know that it's going over to China, so if we think we're going to save the world by telling Canada: 'We're not going to take your oil from Alberta,' that's not going to happen."

Keystone XL has been caught in the crossfire of a heated ideological debate in the United States about fossil fuels versus renewable sources of energy with the State Department slated to make a final decision on the project by the end of the year.

Murkowski's spirited defence of the pipeline, which would carry millions of barrels a week of oilsands crude through six states to the Gulf of Mexico, illustrates how the debate has split along partisan lines.

Republicans are largely in favour of Keystone, saying it will create much-needed jobs and help end U.S. reliance on oil from sometimes hostile OPEC regimes. Many Democrats and the environmentalists among U.S. President Barack Obama's liberal base, meantime, are vehemently opposed, saying the pipeline is a disaster waiting to happen and only prolongs America's gluttony for oil.

Murkowski said it was unrealistic to expect America to curb its appetite overnight.

"If we want to have a world where we can be in a building and it's the temperature that we like, and we can pull out our cellphones and our BlackBerrys and talk to one another…that's not going to happen safely and responsibly unless we can continue to dig a hole."

Republicans tour the oilsands

Her remarks came a day after three fellow Republicans toured the oilsands facilities in Fort McMurray, Alta.

Congressmen Bob Latta, John Shimkus and Joe Wilson said they were impressed by what they saw and added they are more convinced than ever of Canada's importance to American energy security.

Some Democratic lawmakers, meantime, have sent letters urging Secretary of State Hillary Clinton to block Keystone XL, saying the approval process has been hopelessly tainted because TransCanada's chief lobbyist once worked on her failed 2008 presidential election campaign.

They've also raised concerns about allegations that the contractor hired by the State Department to assess the environmental impact of the pipeline, Cardno Entrix, has worked on projects with TransCanada.

In its final environmental analysis released in the summer, the State Department said the pipeline posed no significant risks.

"Rather than acting as fair arbiters to TransCanada's application to build a massive pipeline across environmentally sensitive areas of the United States, State Department officials appear to have acted as little more than cheerleaders for the company's bid," read one letter, from Sen. Ron Wyden of Oregon and two Vermont senators, Patrick Leahy and Bernard Sanders, an independent.

Sanders was to meet with State Department officials on Wednesday to discuss concerns about the pipeline approval process, in particular the environmental assessment.

"The consultant that did that process has been a client of TransCanada to begin with," Sanders told reporters on Capitol Hill on Wednesday. "So we're not quite sure that that process is what it should have been, and we're asking the Department of State to reconsider that."