"You've heard a lot about that 97 percent. That's the only thing that our opponent can say is that 97 percent," said Landrieu, referring the charges from Cassidy and Republicans that she has overwhelmingly voted to support the president's agenda. "The only other thing he can do is be disrespectful to the president of the United States."
Landrieu was echoing what Rep. Cedric Richmond (D-La.) said on her behalf in a radio ad that was apparently aimed at African American voters. "They have shown our president so much disrespect," Richmond said of Cassidy and Republicans.
Asked by The Washington Post afterward what she meant specifically by "disrespectful," Landrieu responded: "He refers to him by his last name. Constantly."
She added: "If you are going to refer to the president of the United States, he's at least earned the title that the people gave him when they elected him."
Landrieu will make two more campaign stops in the afternoon, with just four days left until Saturday's runoff election against Cassidy. Early voting numbers have been encouraging for the Republican, who most observers regard as the clear favorite.
On Wednesday, Cassidy will campaign with former presidential candidate Rick Santorum.
A Cassidy spokesman did not immediately respond to a request for comment on Landrieu's remarks.