‘Down to the Wire’

Definition: used to denote a situation whose outcome is not decided until the very last minute (Source: New Oxford American Dictionary)

The phrase ‘down to the wire’ originates from 19th century horse racing. In order for the judges to decide who won the race, they would string a wire above the finish line. Scribner’s Magazine, July 1889 says:

“As the end of the stand was reached Timarch worked up to Petrel, and the two raced down to the wire, cheered on by the applause of the spectators.”