President Obama says he will be closely involved in the decision on whether to approve the controversial Keystone XL oil pipeline that has pitted two of his key constituencies, labor unions and environmental groups, against each other.

In an interview Tuesday with Omaha, Neb., ABC affiliate KETV, the president suggested he will personally weigh the economic and environmental impact of the proposed pipeline before offering his input. The administration had previously said the matter would be a State Department decision.

“The State Department’s in charge of analyzing this, because there’s a pipeline coming in from Canada,” Obama said. “They’ll be giving me a report over the next several months, and, you know, my general attitude is, what is best for the American people? What’s best for our economy both short term and long term? But also, what’s best for the health of the American people?” 

The $7 billion pipeline would run from the tar sands of Alberta, Canada, to refineries on the Texas Gulf Coast, crossing through six states, including Nebraska.

TransCanada, the company seeking administration approval for the deal, says construction would create as many as 20,000 new jobs. Environmentalists say the pipeline would expose broad swaths of the country to potential oil spills and that the jobs created would only be temporary.

The prospect of new jobs and potential risks of environmental hazard have energized activists on both sides of the debate to lobby the administration for their cause. Hundreds have staged protests outside the White House and at Obama events around the country. Both groups have warned of consequences for the president in 2012 if he doesn’t act in their favor.

Obama has tried to walk a fine line on the issue, recently acknowledging the concerns raised by a group of protesters during his speech in Denver, Colo., last week, saying “we’re looking at it … no decision’s been made.”

There has been no apparent opposition to the plan from the Environmental Protection Agency or the Pipeline and Hazardous Materials Safety Administration, which have also been reviewing the plan.  Five of the six states through which the pipeline will pass have signed off, with Nebraska the only one to raise concerns.

“We need to encourage domestic oil and natural gas production,” Obama said in the KETV interview. ”We need to make sure that we have energy security and aren’t just relying on Middle East sources. But there’s a way of doing that and still making sure that the health and safety of the American people and folks in Nebraska are protected, and that’s how I’ll be measuring these recommendations when they come to me.”

Environmental groups praised Obama’s comments as a positive sign, but still planned protests outside the White House next week.

“President Obama taking the reins would mean we once again have a shot at a fair process,” Friends of the Earth President Erich Pica  said in a statement. “If the scope and severity of the threats posed by the pipeline are accurately understood, it will be obvious to President Obama that the costs far outweigh the benefits and that he must reject it.”

Obama has said he generally doesn’t favor sacrificing safety and wellness in exchange for more jobs, but hasn’t indicated whether he believes such a trade-off is at play in the pipeline case.

“These are all things that you have to take a look at when you make these decisions,” he said.