nail-biting

The Japan Times Online October 3の米国大統領選挙についての記事 "With Japan in U.S. electoral spotlight, overseas vote could play decisive role" から引用します。
American voters living in Japan are counting down the days as one of the most-watched presidential elections in U.S. history hurtles toward a potentially nail-biting conclusion ― one that could have profound effects for Washington’s ties with Tokyo.
"nail-biting" とは面白い表現ですね。米国では大人でも爪を噛む人が結構いると聞いたことがありますが、爪を噛むのはやはり何かのストレスが原因なのでしょう。"nail-biting" を辞書で確認します。
・Cambridge English Dictionary: A nail-biting situation is very exciting or worrying because you do not know how it will end: Germany won the championship after a nail-biting final.
・Collins Dictionary: If you describe something such as a story or a sports match as nail-biting, you mean that it makes you feel very excited or nervous because you do not know how it is going to end.
確かに、どちらの候補者も人気があるような無いような状況で、どちらら勝つのか分かりませんね。