(CNN) -- They're rich, powerful and P.O.'d.
One of them is BFF with Secretary of State Hillary Clinton.
And they're putting President Obama on notice: stop the Keystone XL oil pipeline or else. Or else what? Well it depends on who you ask.
Take Susie Tompkins Buell, for instance. She's a major Democratic Party fundraiser and co-founder of Esprit clothing company.
This is a woman who's used to hosting political fundraisers and entertaining multimillionaires. She's often described as one of Clinton's closest friends -- donating to her 2008 presidential campaign. Back then, she led a group of holdout Clinton supporters before finally throwing her support to Obama after the '08 Democratic convention.
On Tuesday, Buell could have been rubbing shoulders with the president at a swanky $5,000-a-plate luncheon.
Instead, she joined an estimated 1,000 people out in the street protesting against the pipeline.
"If he doesn't oppose this, I certainly could not get behind him in a big way," she said Thursday. Over the years, she guesses she has raised more than $1 million for Democratic causes and candidates.
Will she be helping out Obama's re-election?
"I'm doing fundraisers for several people coming up in the next few months, but the (Obama campaign) hasn't asked me, and I haven't volunteered -- and I don't know what's to come, I really don't."
Buell wasn't the only rich and powerful political donor at Tuesday's demonstration. Michael Kieschnick, president and co-founder of CREDO Mobile and Working Assets, was there, too.
Obama's decision, he said, "will really be the clearest most unambiguous statement of whether or not he cares about protecting the Earth as he said in his campaign."
Keystone XL is a proposed 1,700-mile pipeline that would carry crude oil from Alberta, Canada, to refineries in Texas. Environmentalists fear the pipeline will poison underground water supplies. Pipeline operator TransCanada says the project would pose no threat, create jobs and spur the sagging economy.
Obama has said the decision whether to begin pipeline construction rests with the State Department, but opponents say the final call is in the president's hands. The administration's decision is expected before the end of the year.
Buell said she's spoken about the Keystone issue recently with her friend the secretary of State at a social gathering a few weeks ago.
"She knows that it's important for the people to speak out," Buell said. In 2010, Clinton said the State Department had not yet completed its analysis of the pipeline's environmental effects, but it was "inclined" to "sign off" on the project.
At the demonstration Buell, who has seven grandchildren, held a poster that said, "Another outraged grandmother against the pipeline."
"I don't say that I know President Obama, but I've had several conversations with him," Buell said. "I feel that the environment is not a priority for him, and it should be."
Obama re-election campaign press secretary Ben LaBolt wouldn't respond directly to Buell's comments, but he did offer a written statement that said, "The president has done more to wean us off of foreign oil and transition the nation to a clean energy economy than any other -- investing in renewable energy and high-speed rail, building a smart grid and reaching a historic agreement with the automakers on fuel economy standards that will save us from importing millions of barrels of oil from the Middle East. When Americans compare the president's record promoting clean energy and America's energy security to those of the leading Republican candidates, who don't even believe that climate change is an issue that we need to address and would cede the clean energy market to China, there will be no question about who will continue our progress."
The environmental community sees the Keystone pipeline as more than a threat to water in the heartland. They see it as a political test of Obama's 2008 campaign promise to cut U.S. dependence on polluting fossil fuels and to slow climate change. Allowing the project to move forward, they say, makes a statement that the White House is willing to bow to the wishes of the powerful oil industry.
Kieschnick's business has donated $5 million to groups that oppose the pipeline. A self-described "big and enthusiastic" Obama supporter in 2008, Kieschnick said he made $4,400 in personal donations to the president's first campaign.
He also was among 1,200 pipeline protesters who were arrested outside the White House last summer. But Kieschnick hasn't given up hope. He still has a photo of himself with Obama hanging on his office wall.
Basically, he says, if the pipeline starts going, the money stops flowing. "I would still vote for him, and I would work to defeat his opponents," Kieschnick said, "but nothing more."
It's not the first time disgruntled Democrats have threatened to withhold their support for Obama. During debt ceiling negotiations with Congress in July, the Progressive Change Campaign Committee demanded that the president press Congress to raise taxes on higher income earners and protect entitlements -- or else lose the committee's support.
Members of the group threatened not to contribute to or volunteer for the president's re-election campaign unless the White House met its demands.
Last summer, the liberal group MoveOn.org, which supported Obama in 2008, expressed frustration with the president over what it said was his inability to hold firm against Republicans in debt ceiling battles and on environmental issues.
Environmentalists acknowledge the White House has made some positive steps, including new vehicle fuel efficiency standards aimed at saving energy and cutting pollution.
But if Obama allows Keystone to go forward, they say there will be political repercussions.
Donors like IT consultant David desJardins say the campaign will have a hard time motivating its base in an election where turnout may be critical. "Even if the Sierra Club says we should still go out and support the president, people will say, 'Why should we do that when he didn't stand up for us when he really had the chance?'"
In 2008, ex-Google software engineer and philanthropist desJardins watched from the audience as Obama delivered his nomination acceptance speech promising to fight climate change and pollution.
Now Keystone offers a chance for "Obama to do the right thing, and then give a great speech about how we need to stop investing in environmental degradation and nonrenewable energy sources and start investing instead in renewable energy," desJardins said. "Then I would certainly be inspired to make a contribution."
Protest organizers admit their message has been overshadowed somewhat by the nationwide Occupy Wall Street protests. But rather than compete for media attention, the two groups have been helping each other to some extent, joining forces at protests and offering moral support, organizers said.
Nonetheless, the anti-Keystone groups are preparing a new demonstration set for November 6, a year before Election Day, when thousands of pipeline opponents plan to form a human circle around the White House.