Democratic Senate candidates surged to victory in Iowa, Kansas, Maine, North Carolina, Ohio, South Carolina, and Texas – and could win more still. Dems are also on pace for a sizable House majority.

"This is the worst electoral defeat in my lifetime and likely in history," said one GOP operative.

Your very own manual to help track the crucial U.S. election results on Tuesday night, and what Democrats need to do to win back control of Congress.