In Louisiana Runoff Election, Senator Landrieu Tries to Revive Her Base

She has been rebuffed by her liberal colleagues in Washington and pilloried at home for voting with the president, and has watched helplessly while her Democratic base has eroded like a cheap levee.

These are hard times for Mary L. Landrieu, the last Deep South Democrat in the United States Senate.

But on the cusp of a Saturday runoff election that feels as much like a race against history as against a Republican opponent, Ms. Landrieu has been barnstorming around her home state on what she called her “Louisiana First Victory Tour,” hugging, kissing and cajoling voters with an argument that has served her well for the 18 years she has been in the Senate.

On the stump, Ms. Landrieu, 59,