Polls show the sister of the late Senator Lindsey Graham in a virtual tie with her Democratic opponent, Dr. Annie Andrews. An upset was unthinkable just a few months ago.

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South Carolina seems like a serious race; Minnesota may not be; and Florida still appears out of reach for Democrats.

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Senator Darline Graham, the South Carolina Republican, is struggling to replicate her late brother’s success. Republicans lead in the Florida Senate race and Democrats are up in Minnesota.

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