Barring a last-minute miracle, Sen. Mary Landrieu, D-Louisiana, will lose a runoff election to her Republican challenger, Rep. Bill Cassidy, on Saturday.

"She certainly she is fighting to the end, and she is campaigning hard," said CBS News congressional correspondent Nancy Cordes, but "a lot of Democrats have already resigned themselves to the fact that she likely is going to lose."

It stands to be an unfortunate turn of fate for Landrieu, the scion of a storied Louisiana political family who has represented the state in the Senate since 1997.

But it's hardly surprising: Landrieu has watched many of her fellow white, Southern Democrats fall to GOP challengers in the last several cycles. Her defeat, if it comes to pass, will mark the end of an era - the departure ofthe last white Democrat to represent the Deep South in Congress.

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The South was once Democrats' most reliable stronghold: Before the passage of the Civil Rights Act of 1964, Democrats enjoyed a monopoly over statewide elections in the South, holding all of the region's governors' offices and Senate seats. That grip began to slip in the decades that followed, but as recently as a decade ago, Democrats still held a majority of senate and gubernatorial seats in the Deep South. Not a single one will remain in their control after November's victors take office next year.

"It's not just that Senate Democrats have been wiped out in the South," explained Cordes. "It's that there are no longer any Democratic governors. There are no longer