ROUGH CUT (NO REPORTER NARRATION)<br/> <br />U.S. Senators debated the Keystone XL oil pipeline ahead of a vote late on Tuesday (November 18), which supporters hope will send a bill clearing the way for the controversial project to President Barack Obama.<br/> <br />With the chamber apparently one vote short of ensuring the bill could overcome procedural obstacles, supporters including Democratic Senator Mary Landrieu were working hard to find more support.<br/> <br />"The main reason is it will signal a great sign that America understands that energy independence for our nation is possible for the first time ever. And when I mean energy independence, I mean energy independence for the North American continent," Landrieu said, speaking from the Senate floor.<br/> <br />Construction of Keystone has broad support in Louisiana, an oil producing state, where Landrieu faces an uphill battle to win a new six-year term in a December run-off election.<br/> <br />Backers of the bill in the 100-seat Senate, currently co
