.....nothing, according to a study done by two researchers from NTNU. By asking interviewees a series of questions immediately following a televised debate - including fact-oriented questions and placing type questions where the interviewee was asked to place a party to the left or right based on statements made during the debate, they concluded that the viewer gets no useful new information whatsoever. Why? Because the politicians rely too much on emotion-based rhetoric and because they rely on having short sound bytes in which to present their arguments and provide a rebuttal, thus essentially reducing the debate to a spewing of slogans.
And less than one week away from the election date, all campaigning/slogan chanting is still done by national politicians about national issues in a local election. Where are your local representatives? Not even in the local newspapers, unless they cheat on their taxes or screw up in other ways. They're standing in the town square handing out pamphlets in their hopped up lemonade stands.