The interview is one of the most successful tricks that politicians and the media plays on voters. A politician will do an interview with a journalist that (secretly or not-so-secretly) supports that candidate. The journalist will ask a tough question that the voters have been wondering about. The politician will give an answer that touches on the subject but doesn't really answer the question. Then, the journalist will move on to a new question, no follow-up on the previous question.
This way, the politician can say that the question has been asked and answered and now we need to move on. Obviously the only people still asking for an answer are from the other party and have an agenda.
Or people who noticed that it wasn't really answered in the first place.
Some politicians are worse about this than others, but have no doubt, any of them will use this if they can. ("If they can" means they have to have a willing journalist participating. This is harder for some politicians than others.)