How do you know what emerges in the last minute news is true?
If that were valid, all the candidates would say something really rotten about each other the last couple of days and get it in the news. Wouldn't that be a fiasco?
You don't - nothing is for sure in this world, voting is just a process of sifting through a bunch of information, sorting through evidence, determining what substantiates what, using some common sense, examining your hunches, then holding your nose and with trepidation marking the ballot. Nothing that any politicians says about anything should be regarded as "news".