* U.S. House would vote on separate proposals
* Energy, transit proposals spark controversy
* Obama wants big changes in any final bill
By John Crawley
WASHINGTON, Feb 14 (Reuters) - Republican leaders approved procedural steps on Tuesday to prevent a $260 billion transportation bill from disintegrating in the House of Representatives as the White House threatened to the veto any final measure that did not include major changes.
Speaker John Boehner and his lieutenants, concluding they did not have enough support within their own ranks to ram the bill through the chamber, decided to break the proposal into three pieces and vote on each separately.
This approach, they believe, would simplify debate and slow the momentum of Democrats and some Republicans who have threatened to derail the five-year bill over politically charged energy and funding provisions.
"We are determined to allow as many members to participate and offer their amendments on the floor as possible," Boehner and House Rules Committee Chairman David Dreier said in a statement. "The process will facilitate this."
Infrastructure is considered an economic stimulus, and Republicans and Democrats are under election-year pressure to create jobs with unemployment easing but still stubbornly high.
Most recent Transportation Department figures show that 27,000 jobs are created for every $1 billion in federal spending on road, bridge and transit construction.
Measures to be considered separately in the House in coming days include controversial proposals approved by the chamber's energy, tax writing and transportation committees.
These initiatives would fund part of the transportation bill through expanded domestic oil and gas drilling, would fast-track the stalled Keystone XL oil pipeline from Canada to Texas and would remove dedicated funding for mass transit.
Approved measures then would be repackaged into a single transportation plan that would serve as the basis for the House in any negotiations with the Senate on a final bill.
A two-year, $109 billion transportation proposal working its way through the Senate has its own hurdles to clear. Republicans there are also pushing for the Keystone pipeline.
President Barack Obama's top deputy on transportation, Ray LaHood, has described the House version as the worst proposal of its kind that he has ever seen. "It's a lousy bill," LaHood, a former Republican congressman from Illinois, said this week.
The White House followed up late on Tuesday with a statement formally opposing the House measure as written and threatening a presidential veto if a number of elements were included in any final bill passed by Congress.
Specifically, the administration said it strongly objected to the Keystone proposal and the oil and gas drilling plan that includes opening up Alaska's Arctic National Wildlife Refuge to exploration.
TransCanada Corp is the chief backer of the Keystone pipeline.
Obama also opposes the proposal to change transit funding, which Democrats and many Republicans say would short-change long-term resources for subway, bus and light-rail projects.
A sharply divided Congress has been unable to agree on a new law authorizing long-term federal spending on transportation programs. The last one expired in 2009 and a series of temporary spending bills have filled the gap since.
The current stop-gap spending bill expires on March 31.
Neither chamber is considering Obama's proposal for a six-year, $476 billion transportation plan that would be funded with savings from war spending.