U.S. Sen. Mary Landrieu framed Louisiana's Senate election as a referendum on her three terms in office, not the policies of President Barack Obama.

In the first TV debate featuring all three major contenders in the race, Landrieu on Tuesday defended her vote for Obama's federal health care overhaul. But she distanced herself from Obama's energy policies and talked of her work with multiple presidents over the years, both Republican and Democrat.

Her main Republican challenger, Rep. Bill Cassidy, repeatedly tied the Democratic incumbent to Obama's policies, saying a vote for Landrieu would be a vote for the president's agenda.

GOP candidate and tea party favorite Rob Maness positioned himself as the Washington outsider, criticizing both his opponents as career politicians who endanger the future of the nation.