WASHINGTON -- With the clock ticking, supporters of a Senate bill to approve the Keystone XL pipeline are still scrambling to find the last vote.
With 59 Senators publicly voicing support, the hunt was on for the 60th vote before a critical vote Tuesday to advance the measure. Maine independent Sen. Angus King left the possibility open, telling reporters he was a "probable no."
All 45 Republicans support it, and 11 Democrats have signed onto the bill, along with three others who have publicly said they will vote "yes."
That leaves just one.
The issue has taken center stage in the waning days of this Congress in the hopes it will boost the prospects of Louisiana's Senate candidates.
The bill has fallen victim to Senate gridlock in the recent past, but Sen. Mary Landrieu, with her political career at stake, launched an effort last week to find enough Democratic converts for passage. She trails Rep. Bill Cassidy, R-La., in the polls in advance of a Dec. 6 runoff election in Louisiana, but is campaigning as a skilled and seasoned lawmaker with the ability to pass bipartisan legislation vital to her oil-rich state.
The House passed legislation last week to allow construction to proceed, with Cassidy claiming much of the credit.
The vote offers a preview of what is ahead for President Barack Obama on energy and environmental issues when the Republicans take control of both houses of Congress next year. Even if the measure fails Tuesday, Republicans in both chambers vowed to try to approve Keystone again.
For six years, the fate of the Keystone XL oil pipeline has languished amid debates over global warming and the country's energy security. The latest delay came after a lawsuit was filed in Nebraska over its route.
The White House has issued veto threats of similar bills, and both administration officials and Obama have indicated a veto is likely. Landrieu said last week that neither the Senate nor House has the two-thirds majority needed to overcome a veto.
The proposed crude-oil pipeline, which would run 1,179 miles from the Canadian tar sands to Gulf coast refineries, has been the subject of a fierce struggle between environmentalists and energy advocates ever since Calgary-based TransCanada proposed it in 2008.
AP Special Correspondent David Espo contributed to this report.