The politics around the Keystone XL pipeline took another twist on Thursday when Democratic presidential candidate Hillary Clinton put the White House on notice, saying the decision on the proposed oil pipeline was taking too long.

'The president is probably going to say OK — stew in your own juices.' - Christopher Sands, Hudson Institute

"I worked in the administration, I started the process that was supposed to lead to a decision, I can't wait too much longer and I'm putting the White House on notice. I'm going to tell you what I think soon, because I can't wait," Clinton told a town hall-style campaign event in New Hampshire.

That statement raises a whole bunch of questions.

Why send the message through the media? Can't she say this directly to U.S. President Barack Obama's administration, in which she used to work? If she has an opinion on Keystone XL, why continue to wait to share it? After all, we know where her main rivals for the Democratic nomination sit on the pipeline. Both Bernie Sanders and Elizabeth Warren are opposed to the pipeline.

The White House said last month the U.S. State Department continues to review TransCanada Corp.'s proposed Keystone XL pipeline from Canada's oilsands to Gulf Coast refineries.

Clinton thought to be in favour

During her time as secretary of state, Clinton did oversee the review of the pipeline and the feeling was that she was pro-Keystone. She'd been supportive of the process and thought that there had been a thorough review.

Clinton is in a classic Catch-22. Although she positioned herself as a centrist early in the campaign, there's no upside in declaring a stance on the pipeline.

Coming out in favour of the pipeline would alienate the the progressive wing of the party during primary season. Opposing it would alienate the states where support for the pipeline is strong.

It seems as though she's choosing to make that shift to the left, according to Chris Sands, a senior fellow at the Hudson Institute, an American conservative non-profit think tank based in Washington, D.C.

Trouble in the campaign

"As she's had trouble on the speaking circuit, she's positioned herself to the left to capture some of the energy within the Democratic Party on the environmental side," said Sands.

"Because of the challenge that she's faced from Bernie Sanders and to some extent from Elizabeth Warren."

What Clinton really wants is for the decision to go away, for the Obama administration to make the call, one way or another, and get it off her plate.

The Biden factor

There were signs in the summer that might happen, but then Vice-President Joe Biden considered entering the race, which added another level of complexity to the politics.

"Biden suddenly seemed to be more the Obama camp's favourite candidate," said Sands. "And Hillary Clinton was again on the defensive, and Obama stayed silent."

Sands also said that it's interesting that Clinton chose to make a public plea, instead of a private one.

"She's so far outside, she's telling the press this in the hopes that he'll make his call," Sands said.

Obama, in the past has not responded to ultimatums on Keystone XL, and Sands said it's not likely that he will do so now.

"The president is probably going to say OK — stew in your own juices," Sands said.

With files from Reuters