himself in some serious hot water over
himself in some serious trouble/problems about something
(Young man, if you are not home by midnight, you are going to be in hot water with your father!)
She is now a write-in candidate.
She is now an informal/unofficial candidate.
(There are three official candidates for club president. You and your friends want someone else to be president, so during the election process "you write in his/her name on the ballot", making that person a "write-in candidate".
They are running neck and neck,
(Josi did a wonderful job explaining this.)
Republican Joe Miller in a
virtual dead heat with write-in Lisa
Republican Joe Miller in a very close race (another expression taken from horse racing) with Lis Murkowski, an unofficial-informal candidate (see above)