The Republican-controlled U.S. House of Representatives has passed a bill approving the Keystone XL oil pipeline. The proposal now moves on to the U.S. Senate.

The House voted 252-161 Friday on the bill sponsored by Republican Representative Bill Cassidy of Louisiana. It was put forward in a bid to boost his chances to take over Louisiana's Senate seat from Democrat Mary Landrieu.

The two are headed for a December run-off. Landrieu successfully pushed the Senate to vote on the measure next week.

Senate supporters said they were confident they'd have the 60 votes needed for passage Tuesday. But the new representatives elected in midterms won't be sitting in the Senate until January. Instead, Landrieu is frantically politicking behind the scenes to gather enough votes.

9th attempt to get House approval

The bill marks the ninth attempt by the House to secure approval of the pipeline, which has been repeatedly delayed by environmental reviews, legal challenges to its route and politics. Prior votes in the Senate on the issue have failed to get enough votes, but supporters said Thursday they were close to reaching that threshold.

Both the GOP and Senate Democrats hope the votes will give an edge to their party's candidate in the Louisiana Senate race, where Republican Rep. Cassidy and Sen. Landrieu are headed for a runoff and both touting their energy credentials in an oil and gas-producing state.

While Landrieu pushed for the vote planned in the Senate next week, Senate Minority Leader Mitch McConnell of Kentucky credited the Republican sponsor, Sen. John Hoeven of North Dakota, for the progress Thursday.

"We never would have gotten to this point without the tireless leadership of Sen. Hoeven in the Senate, and Congressman Cassidy in the House," said McConnell. "Like the experts, Sen. Hoeven also knows that Keystone would also have almost zero net effect on our climate."

Despite the declining price of oil, Republicans believe the pipeline would mean a boost in economic activity that would benefit their constituents.

Obama leans toward veto

The Washington Post, citing aides, reported Thursday that President Barack Obama is prepared to veto the bill. His reasoning would be that the State Department hasn't completed its review of the process, and that state supreme court in Nebraska, through which the pipeline would pass, has yet to rule on a key part of the pipeline’s route.

The president again came out against Keystone Friday, saying it would benefit Canada, but it wouldn’t help U.S. consumers get cheaper gas.

"Understand what the project is — it is providing the ability of Canada to pump their oil, send it through our land down to the Gulf, where it will be sold everywhere else," Obama said.

"It doesn’t have an impact on U.S. gas prices," he added.

Duane Bratt, chair of the Department of Policy Studies at Mount Royal University, says Obama's remarks misrepresent how the North American energy market works.

"There is so much wrong with that statement," he told CBC News. "It ignores the undercapacity of U.S. refineries. Having additional oil coming into U.S. refineries is good for them."

It also implies that Canada plans to ship oil to China and India, when most of Canada’s petroleum is sold in the U.S., Bratt said.

Alberta Premier Jim Prentice told CBC’s Power & Politics he has to be respectful of the American process. "Some of the comments that have been made are not very encouraging,” he said. “We'll continue to advocate that this is a project that's in the best interest of both countries."

Prentice said he believes the U.S. will come to see that a pipeline is a safer, cheaper way to ship oil than rail.

When the Keystone pipeline was first proposed, there was no shale oil production in the U.S.

Calgary-based oil analyst Jackie Forrest says the shale oil that is now so abundant doesn’t need as much refining, so Gulf Coast refineries are looking for heavy oil, such as crude from Canada’s oilsands.

“There is a shortage of heavy oil,” she told CBC News. “If we can get our oil to the Gulf Coast, there is a market for it there.”

Test of climate change commitment

The bill specifically accepts a U.S. environmental impact study issued by the secretary of state in January, saying it "shall be considered to fully satisfy" other pending environmental and endangered species reviews.

As well, the bill mandates that any appeal against permit requirements must be expedited straight to the U.S. Court of Appeals.

Environmentalists have framed the issue as a significant test of Obama's commitment to address climate change. Republicans, and the State Department's review, say the pipeline won't have a significant impact on global warming and thus should be green-lighted.

The 1,700-kilometre project is proposed to go from Canada through Montana and South Dakota to Nebraska, where it would connect with existing pipelines to carry more than 830,000 barrels of crude oil a day to refineries along the Texas Gulf Coast.

Supporters of the pipeline say it will create thousands of jobs and aid energy security, but environmentalists warn of possible spills and say the pipeline will expedite development of some of the dirtiest oil available.

The State Department said in a Jan. 31 report the project would not significantly boost carbon emissions because the oil was likely to find its way to market by other means. It added that transporting it by rail or truck would cause greater environmental problems than if the Keystone XL pipeline were built.

With files from CBC News