Story highlights At least 60 senators will vote to advance legislation authorizing the Keystone XL pipeline, Sen. Mary Landrieu says

The Louisiana Democrat is trying to pass the bill in time to help in her Dec. 6 run-off election against Republican Bill Cassidy

Louisiana Democratic Sen. Mary Landrieu says she has the 60 votes she needs for the Senate to advance a measure Tuesday that would authorize construction of the Keystone XL pipeline.

Landrieu has been scrambling to attract at least 15 Democrats to join 45 Republicans to reach the critical 60-vote procedural threshold. She told reporters at the Capitol on Monday night that she'd reached that mark.

"I feel very comfortable," Landrieu said.

Photos: Photos: Louisiana's Senate race Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Democratic Sen. Mary Landrieu addresses supporters at her headquarters in New Orleans on Tuesday, November 4. Landrieu and Republican candidate U.S. Rep. Bill Cassidy are projected to be in a December runoff after neither candidate reached the 50% threshold to win outright. Hide Caption 1 of 12 Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Cassidy addresses supporters during his election-night watch party in Baton Rouge on November 4. Hide Caption 2 of 12 Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Landrieu gives a thumbs up while voting November 4 in New Orleans. Hide Caption 3 of 12 Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Cassidy tours the Livingston Parish Detention Center during a campaign stop in Livingston Parish on Monday, November 3. Cassidy currently represents Louisiana's 6th Congressional District. Hide Caption 4 of 12 Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Retired Air Force Col. Rob Maness, right, speaks with a voter last month during the Louisiana Gumbo Festival in Chackbay. Maness, a Republican, trailed Landrieu and Cassidy in the Senate race. Hide Caption 5 of 12 Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Landrieu speaks during a news conference April 1 urging Congress to pass the Paycheck Fairness Act. Hide Caption 6 of 12 Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Cassidy speaks May 31 on the final day of the Republican Leadership Conference in New Orleans. Hide Caption 7 of 12 Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Maness speaks May 29 during the Republican Leadership Conference. Hide Caption 8 of 12 Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Landrieu poses for a selfie in September with football fans tailgating at Louisiana State University in Baton Rouge. Hide Caption 9 of 12 Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Cassidy, center, admires the seersucker outfits of his fellow Congress members on June 11. Hide Caption 10 of 12 Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Maness sits on an alligator while shooting a campaign commercial in May. Hide Caption 11 of 12 Photos: Photos: Louisiana's Senate race Louisiana's Senate race – Cassidy shakes hands with Maness before the three candidates debate one another October 14 at Centenary College in Shreveport, Louisiana. Hide Caption 12 of 12

JUST WATCHED Keystone protest on Sen. Landrieu's yard Replay More Videos ... MUST WATCH Keystone protest on Sen. Landrieu's yard 00:38

JUST WATCHED Dems consider Keystone vote for Landrieu Replay More Videos ... MUST WATCH Dems consider Keystone vote for Landrieu 01:25

JUST WATCHED Clinton: Keystone XL just one pipeline Replay More Videos ... MUST WATCH Clinton: Keystone XL just one pipeline 02:27

At least 14 Democrats have said they will support the measure. But it's not clear who has agreed to provide the final vote or whether Landrieu's comments simply reflect optimism.

One of Landrieu's top targets, West Virginia Sen. Jay Rockefeller, said it won't be him. Another target, Maine Sen. Angus King, an independent who caucuses with the Democrats, said he is leaning against supporting the bill.

If she can shepherd the legislation through the Senate, it would allow Landrieu to demonstrate her influence one last time ahead of a Dec. 6 run-off election in Louisiana, where she faces Republican Rep. Bill Cassidy, who sponsored the bill authorizing the pipeline when the House approved it on Friday.

If the Senate ultimately passes the Keystone bill, a confrontation could emerge between Congress and President Barack Obama. The president said at a news conference late last week that he doesn't want Congress to intervene in the State Department's long-running consideration of the project -- and offered his most specific critique of it yet.

"Understand what this project is: It is providing the ability of Canada to pump their oil, send it through our land, down to the Gulf, where it will be sold everywhere else. It doesn't have an impact on U.S. gas prices," Obama said at a Friday news conference in Myanmar.