I know how to make sure you get a correct answer.
Find out if the politician has family, people he cares for, the stronger the bond the better. Wikipedia will make this easy for the TV show producers.
Abduct the politician and whoever he cares about, kids, wives, brothers, life long friends.
Lock the politician in the middle of a dark room in an animal cage, lock his family in small animal cages around the target unable to touch each other, all naked, keep the room dark and cold, place a red glowing LED style clock above the door that can be manipulated from the outside. Make sure to have bright florescent white lights in the hallway. Have the place wired with thermal cameras and sound.
The interrogator walks in and explains this is all a game and the rules are to follow.
This is a game between the interrogator and target. If the interrogator wins, the entire family will be dead, this will result in the death of the target. If the target wins, he and his family will be released .
The clock on the wall is the punishment clock, if that time runs out, he loses someone he cares about.
Being truthful adds time, lying will remove time off the clock and someone he cares about will be punished.
Explain He will be asked questions that have already been asked to others, the interrogator is just looking for confirmation of intelligence before it can be reported to the President of the United States. (This makes him think he's important and he's not giving any information that isn't already known, but that's a lie)
Ask a question the target can't possibly know, when he says he doesn't know or lies, punish one of his family members. For example, if the target has a very young small child, the interrogator can blast them with a CO2 fire extinguisher, it simulates suffocation and the cold will cause mild frostbite.
Tasers, cattle prods, pepper spray, high pressure fire hoses, CO2 fire extinguishers, etc are all very effective, and they do not do a lot of damage.
You can move up to harsher techniques if the target is resistant.