Supporters and opponents of the proposed Keystone XL pipeline are launching ad campaigns south of the border in a last-ditch effort to influence the White House’s final decision on the controversial project.

The PR blitz has been put into overdrive, pitting environmentalists against political supporters as both Canadian and U.S. officials wait to see if U.S. President Barack Obamawill put his final stamp of approval on TransCanada Corp.’s proposed pipeline.

The pipelinewould transport oilsands bitumen 3,200 kilometres, from Alberta to refineries along the U.S. Gulf Coast. 

While supporters say the $7-billion project would bring jobs and economic growthto Canada, opponents say a cross-border pipeline would be an environmental nightmare. 

The All Risk, No Reward Coalition, a U.S.-based organization comprised of several environmental groups, has spent hundreds of thousandsof dollarson a national ad campaign now airing on major U.S. networks.

The campaign says the pipeline’s environmental risks outweigh its benefits, and urges top U.S. officials to kill the project.

“We’re getting closer to when the president is expected to make his decision and we want to highlight the fact this pipeline is nothing but risks and has no rewards for America,” said Jeff Gohringer, of the League of Conservation Voters, one of the organizations involved in the ad campaign.

On Monday, Alberta will launch its own $70,000 ad campaign that will appear in U.S. Beltway newspapers. The ads describe Keystone as “the choice of reason” that would provide “more energy from an ally with a strong environmental track record.”

“We’re the closest neighbour, we’re the closest strategic ally in the world, and we’re working hard to ensure that America, and the leadership of America, understands that,” said Alberta Energy Minister Ken Hughes.

Alberta Premier Alison Redford is travelling to Washington on Monday in an effort to convince environmentalists that there’s nothing to fear from the pipeline.

“We know that whenever this discussion comes up the decision-makers in Washington want to know what our environmental record has been,” she said. “We want to be able to talk about that.”

Redford may face tough new questions from lawmakers as crews continue to clean up an oil spill in central Arkansas. More than a week ago, a pipeline operated by Exxon Mobil burst, spilling thousands of gallons of Alberta crude into a suburban neighbourhood, forcing some 20 homes to be evacuated.

The oil spill, environmentalists have warned, illustrates the potential dangers of the Keystone line.

Obama is expected to announce his decision on Keystone sometime this summer. 

With a report from CTV’s Richard Madan