OTTAWA, April 30 (Reuters) - U.S. President Barack Obama is unlikely to deliver his verdict on TransCanada Corp's Keystone XL pipeline between mid-June and mid-October for fear of being seen as interfering in Canada's upcoming election, said three Ottawa-based sources familiar with the matter.
Two of the sources said Obama - whose relations with Conservative Prime Minister Stephen Harper are generally cool - realized there was a risk that a decision before the election could be seen as a bid to influence the Oct. 19 vote.
"The announcement will not be made while Canada is focused on the election," said one of the sources.
Although the 36-day Canadian campaign is not officially due to kick off until Sept. 14, electioneering will start the day Parliament breaks for the summer on or about June 19.
There is historic precedent for Washington to be cautious. In 1963, when relations between President John F. Kennedy and Conservative Prime Minister John Diefenbaker were poisonous, the United States accused Ottawa of not meeting its commitments to NATO.
The move triggered a crisis for the Conservatives and prompted Diefenbaker to call an election, which he lost. It is widely accepted in Canada that Washington had interfered.
Obama is under pressure from environmentalists to veto the northern leg of the pipeline, which would cross the border and carry crude from Canada's oil sands to U.S refineries. Obama has recently made critical comments about Keystone XL, which is strongly backed by Harper's government.
The election looks to be a race between the Conservatives and the opposition Liberals, who also back Keystone, and would most likely turn a veto by Obama into a campaign issue.
Thus any pre-election announcement by Obama seems unlikely, unless he were trying to send a message.
"Diplomatically, that would be very unwise," said a second source closely familiar with Canadian government thinking.
In Washington, the White House and the State Department declined to comment.
The Obama administration has taken six years to decide whether to approve the pipeline, prompting public complaints from Harper and other senior Canadian officials. Obama told Reuters on March 2 that a decision would be made "before the end of my administration, definitely."[ID: nL1N0W42EH]
Andrew Cohen, a professor of international affairs at Carleton University and an expert on Kennedy, said he doubted Obama would make an announcement during the election, even though his relationship with Harper was not good.
"But it is at Diefenbakeresque levels? No, that was a hatred," he said. (Reporting by David Ljunggren; Editing by Dan Grebler)