OTTAWA - Some lobbyists for a controversial pipeline project stretching from the Alberta oilsands to the Gulf of Mexico need no introduction to confidantes of U.S. President Barack Obama.

TransCanada Corp. (TSX: TRP) has recruited heavyweights from the presidential campaigns of Obama, Secretary of State Hillary Clinton and Massachusetts Senator John Kerry to lobby for the proposed Keystone XL oil pipeline.

The effort is part of the Calgary company's full-court press behind closed doors to get Keystone XL approved.

But TransCanada says the hired guns have not opened any inner doors in Washington.

"What we're doing in Washington is no different than what many other groups are doing," company spokesman Terry Cunha said in an interview.

"I know some groups have tried to link that, you know, this may result in us having additional meetings of some kinds. But the Department of State is very transparent on who they're meeting with."

TransCanada has ramped up its spending on lobbyists since it filed an application to extend the pipeline. According to OpenSecrets.org, a website that tracks U.S. federal campaign contributions and lobbying activity, TransCanada and its subsidiaries have spent close to $2 million since 2009 on lobbyists.

Cunha says not all that money was spent lobbying for Keystone XL.

The corporate lobbying comes amid a political push by members of Prime Minister Stephen Harper's Conservative government and Canada's ambassador to the United States to get the project approved.

"Our job is to make sure it's a fact-based decision, on merit," Ambassador Gary Doer told The Canadian Press this week.

The $7-billion pipeline extension cleared a major hurdle recently when the U.S. State Department concluded it would not harm the air or water along its 2,673-kilometre route, nor would it increase greenhouse gases.

Even though it seems likely Keystone XL will get the green light, a Conservative cabinet minister said Wednesday he is not "taking anything for granted."

"We respect, of course, the decision-making process in the United States. It's up to the secretary of state to look at this project," Natural Resources Minister Joe Oliver said in Ottawa.

"We are increasingly optimistic about the likelihood of a presidential permit, which will be based on his analysis of the national interest."

The State Department has until the end of the year to decide whether granting a permit is advisable. There will also be hearings in states along the pipeline route.

Expect officials at those hearings to get an earful.

More than 1,000 people -- including Hollywood actress Daryl Hannah and Canadian author Naomi Klein -- have been arrested at the White House gates protesting the pipeline. Canadian activists plan to hold a protest in Ottawa later this month.

Opponents say Keystone XL is an environmental disaster waiting to happen, pointing to a number of recent pipeline spills. They also oppose Alberta's oilsands because of their high greenhouse-gas emissions.

Advocates say the pipeline will create thousands of American jobs amid a lingering recession, and will also help end U.S. dependence on Middle East oil.

The lobbying over Keystone XL has been wide-reaching.

Public filings show that this year, TransCanada has lobbied officials from the White House and the executive office of the president, members of Congress and several federal agencies, including the state and energy departments.

Many lobbyists are familiar faces to the people being lobbied.

Paul Elliott, the top lobbyist for TransCanada, was national deputy director of the Clinton campaign when the former first lady ran for president in 2008. It is Clinton's department that would grant the permit to authorize the Keystone XL expansion.

Clinton was asked about another pipeline last October during a talk at the Commonwealth Club of San Francisco. In her answer, she appeared to be referring to the Keystone XL pipeline, saying the State Department leans toward signing off on it.

"We haven't finish all of the analysis. So as I say, we've not yet signed off on it," Clinton said at the time.

"But we are inclined to do so and we are for several reasons -- going back to one of your original questions -- we're either going to be dependent on dirty oil from the Gulf or dirty oil from Canada."

TransCanada hired Elliott in November 2008, Cunha said, around the same time Obama won the election. The spokesman said Elliott was not hired for his political connections.

Earlier this year, the State Department denied a Freedom of Information Act request that environmental groups filed seeking a record of correspondence between Clinton and Elliott.

According to OpenSecrets.org, TransCanada has also paid outside firms Bryan Cave LLP; McKenna, Long & Aldridge; and Van Ness Feldman to lobby on its behalf.

Cunha said Van Ness Feldman represents TransCanada only on the development of the Alaska Pipeline project, not Keystone XL.

The firms have gold-plated Rolodexes.

Jeff Berman of Bryan Cave was the national delegate director for Obama's 2008 presidential campaign. Before that, he spent 17 years working for former House Democratic Leader Richard Gephardt.

Berman's colleague, Brandon Pollak, worked as deputy regional political director on Kerry's unsuccessful 2004 presidential bid. Another colleague, David Russell, was chief of staff to the late Ted Stevens, a long-serving and influential Republican senator killed last year in a plane crash.

Bandele McQueen over at McKenna, Long & Aldridge was chief of staff to late Democratic congresswoman Juanita Millender-McDonald. McQueen also worked in the Chicago mayor's office, breeding ground for many of Obama's top aides, such as former senior adviser David Axelrod.

The lobbyists were not hired solely for their political connections, Cunha said.

"We've brought on some group to support TransCanada because they all provide a skill set that we feel is necessary for the company for dealing with our work in Washington, D.C.," he said.

The United States does not have the same restrictions that Canada does on lobbying by former public-office holders. Those leaving politics for lobbying in Canada face a five-year "cooling off" period.

A spokeswoman for McKenna, Long & Aldridge directed questions to TransCanada. Neither Bryan Cave nor the State Department responded to interview requests.

The lobbying has not been limited to the United States. The federal lobbyist registry lists 189 entries for TransCanada since July 2008, although not every meeting dealt with the Keystone expansion. The lobbying included talks with Conservative cabinet ministers, MPs, political staff and bureaucrats.