* Wednesday vote is fourth for House on pipeline
* White House has threatened to veto bill
* Rep Lee Terry-"It may not be the last rodeo."
By Roberta Rampton
WASHINGTON, April 18 (Reuters) - The U.S. House of Representatives is scheduled to vote on the Keystone XL project for the fourth time in two years on Wednesday, but the Nebraska Republican who has championed the oil pipeline from Canada knows it well may not be the last.
The pipeline, put on hold by President Barack Obama earlier this year, has taken on an outsized political profile heading into the November elections as Republicans use it to attack Obama's economic and energy policies.
"I've been through the Keystone rodeo before," said U.S. Representative Lee Terry, expressing optimism that, this time, a bill he drafted just might lead to a deal to advance TransCanada's $7 billion pipeline.
But Terry, a senior member of the House Energy and Commerce committee, also recognized that his bill, expected to pass the House on Wednesday as part of a short-term extension of highway and infrastructure funding, faces a rough ride ahead.
The bill would strip Obama of his authority to rule on the pipeline. The White House said on Tuesday that Obama would veto the bill, if it makes it to his desk.
The Democratic president, who has backed the southernmost portion of the line from Oklahoma to Texas, p ut a hold on the rest of the project earlier this year, insisting a portion of the pipeline in Nebraska needs more environmental review.
"We'll keep swinging," Terry vowed in an interview. "It may not be the last rodeo."
Environmental groups have vehemently opposed Keystone because it would bring in crude from Canada's oil sands, which they argue is dirtier than other types of crude oil.
They are concerned about the risk posed by spills from the pipeline, have contested estimates of jobs created by the project, and have raised awareness about the growth in U.S. exports of refined oil products.
Last year, thousands of protesters encircled the White House, and hundreds were arrested.
The state of Nebraska was also concerned that the pipeline's original route went through the sensitive Sandhills region and over a major aquifer.
The state government now supports a new route proposed by TransCanada. Some groups in the state said they plan a legal challenge.
Terry said he expects the Republican-led House will pass a bill later on Wednesday to extends funding for highway and other infrastructure projects until the end of September.
Attached to that bill is his text, which would transfer authority for approving the pipeline to the Federal Energy Regulatory Commission, and require the regulator to quickly issue permits.
The focus would then turn to the Democratic-controlled Senate, which would need to agree to the short-term fix on highway funding.
In March, the Senate agreed on a two-year, $109 billion plan for transportation. The House has been unable to agree on a long-term deal.
The Senate considered adding approval for Keystone to its highway bill, but the measure failed in a 56-42 vote, four short of the 60 votes needed to pass. Obama took the unusual step of calling some senators directly before the vote, asking them to reject the proposal.
Still, 11 Democratic senators voted for the plan. Terry thinks that negotiations on a short-term highway funding bill that includes Keystone could pass a House-Senate conference committee, and that could make Obama rethink the veto threat.
"If we could get enough votes in the Senate, I could almost guarantee the White House would become more reasonable," Terry said.