It’s not that truth doesn’t exist in politics.
It’s that the different kinds of truth that does exist competes through competing interests. When the interests of the people in power become skewed, the notion of truth itself becomes skewed, and the skewing of truth itself becomes the narrative such that the winning policy makers can make a solid claim on truth again.
However, because the losing policy makers, the ones who exploited truth for political gain (Clinton camp) were actually people who had, for the most part, a better handle on the notion of truth than the winning policy makers (Trump camp), we are confronted with a news media that no longer adheres to standards of verifiable, ethically contextualized practice.
This is, for the most part, in my opinion, a phase of the media. We will see that the power structures themselves remain, and I believe that internally, the ethics of correctly contextualizing events will return in some sort of new normal. But for the time being, it seems that no news source can be fully trusted without contextualizng the news source itself. This is difficult if you are not familiar with the journalist or editors of a publication.