Former President Jimmy Carter says he'll endorse Democrat Barack Obama after the polls close on the final primaries. South Dakota and Montana were holding the last primaries Tuesday. Carter told The Associated Press on Tuesday: "The fact is the Obama people already know they have my vote when the polls close tonight." Carter spoke to the AP after addressing the Georgia World Congress Center. Carter, a superdelegate, has remained officially neutral in the race but has offered high praise to Obama. Superdelegates are party officials and elected officials who can vote as they choose at the nominating convention. Carter has noted that his children, grandchildren and their spouses back the Illinois senator.