This week, Alaska Senator Lisa Murkowski may offer an amendment limiting the Environmental Protection Agency's authority to regulate greenhouse gas emissions.

At the same time, Murkowski is also one of the top three Senators in Congress favored by the oil and gas industry, receiving $142,000 in contributions in 2009. Since 2005, Murkowski has received a total of $244,000 from the energy industry, according to the Center for Responsive Politics.

It seems as no surprise that what naturally follows are accusations of undue influence over the Senator on one side and denial of those accusations on the other. What is most apparent is at least an appearance of the possibility of a conflict of interest.

Indeed, one critic, Clean Air Watch president Frank O'Donnell, tells Greenwire (sub. required) that he doubts Murkowski's entire motivation for hobbling the EPA is from the source of her campaign contributions. But "it's hard to avoid the impression that it's a factor," he said. "I don't believe you can buy a senator for $50,000, but you can certainly rent one."

A little help from her friends

Beyond a financial influence over Murkowsi's position on the Clean Air Act, Murkowsi's detractors point at industry lobby influence in drafting legislation. The Washington Post reported last week that two energy lobbyists, Jeffrey Holmstead and Roger Martella, Jr., helped Murkowski write a failed amendment proposal last fall that sought to block the EPA from imposing greenhouse gas regulations on stationary sources for one year.

Holmstead heads up the Environmental Strategies Group at Bracewell & Guiliani. Martella is a partner at Sidley Austin. Two of Holmstead's clients - Southern Co. and Duke Energy Corp. -  are among Murkowski's largest contributors. Federal lobbying records show that at least five others, including Ameren Corp., Arch Coal, Energy Future Holdings, CSX Corp., and Progress Energy, have also contributed to Murkowski's war chest.

Holmstead acknowledged in an interview working with Murkowski and her staff on the amendment.  "I was involved... I certainly worked with her staff," he said, though he denies playing any role in drafting the language for the amendment proposal last fall. Murkowski also maintains that lobbyists held no sway in the text of the document.

Holmstead also says he has no knowledge of his clients campaign contributions, including those made to Senator Murkowski.

Some industry representative have come to the Senator's defense, pointing out that environmentalists are also involved in drafting legislation.

"Senator Murkowski should not be begrudged candid discussions of the Clean Air Act with legal experts any more than her opponents should be criticized for accepting drafting help and contributions from well-heeled environmental groups," said Scott Segal, a lobbyist with Bracewell and Guiliani.

Duke Energy spokesman Tom Williams said there is nothing unusual for "people from all sides of the aisle to comment on legislation. To suggest it's somehow nefarious or inappropriate for one side to do it is inconsistent with reality." Williams has declined comment on Duke Energy's involvement with either Senator Murkowski or Bracewell & Guiliani.

Public interest groups and environmental groups aren't buying it.

The difference, says Tyson Slocum, director of the energy program at Public Citizen, is that lobbying firms are paid for by private companies. While that in itself certainly isn't unusual, "It's rare that we have a lobbyist publicly acknowledging ... ‘Hey, I played a role in this.' There are bad things that happen all the time, and that doesn't necessarily make them right."

"Not only do we have campaign contributions,' Slocum said, "but now we have evidence of active legislative collaboration by a lobbyists representing special interests."

Public Citizen, along with MoveOn.org and public interest groups, are calling on Murkowski to return any campaign donations she received from Holmstead's energy industry clients.

"I think it makes Murkowski's amendment positively radioactive," said Frank O'Donnell from Clean Air Watch, "because it makes it look like she's simply carrying water for businesses that gave her money."

And through all this sits the great state of Alaska, which Murkowski ostensibly represents. A state that is warming faster than most any other place on the planet.