Asymmetry, like so many phenomena these days, is an observable fact to certain scholars, but a doctrine to be denied to others. If asymmetry of the structure and functioning of the political parties is accepted, the journalism standards of NYT and other mainstream outlets is proven obsolete. So far, credible accusations of bias in so-called balanced reporting aimed at the Times have been met by denials. The NYT public editor says that the abstract thinkers who accuse the Times of journalistic failure are themselves biased - abstract thinkers who marshall evidence and draw conclusions in a complex system are more often liberal -- how shocking! So far the Times has stood firm with their conclusion that Trump is not "normal", so that explains the failures of the press. But these failures have been evident for a long time. Sarah Palin could have been the President today, running for reelection, preparing to debate Hillary Clinton, if McCain had won in 2008 and died after two years in office and she had been elected in 2012. So Trump is no outlier as "not normal". So if asymmetry of the parties is true, as it is, then the presumption that "both sides do it" in the exact same way is untrue. That means striving to balance every statement or action that is negative about one candidate with an equal and opposite statement or action by the other candidate, as if this he-said/she-said set up is Newtonian mechanics, is deeply flawed. What's a journalist to do? How about reporting about each candidate separately as if the other candidate does not exist? (At least until they debate).And don't search primarily for flaws. Don't follow every lead fed to you by Fox News or the opposing camp. Try to research and report on the essential truths about each candidate, the good with the bad, with as full a picture as possible. That is the true meaning of fair and balanced. When journalists do that, they are not in fact checking mode. They do not need tax returns for this or the transcripts of speeches. Both Trump and Clinton have been in public life for decades.
For anyone who thinks trying to report as if the other candidate does not exist is impossible, think about the current broken system - chasing down every accusation in wack-a-mole fashion as if the political journalist is incapable of interpretation of events without being biased. A journalist needs to be like a scientist, but seeking expert opinion when necessary and judging that opinion without bias. But a journalist who functions as a "White House Stenographer" as Colbert said, is not doing the job.