My gut feeling is that we're going to see the Clinton campaign do an imitation of a failed Space-X landing over the next 2-3 months. Like a bad driver sliding on ice, they're going to over-correct and otherwise do the exact opposite of what they need to. It'll be a flaming wreck moving at high speed by the end of August.
My gut on Trump (which hasn't exactly been reliable so far) is that something (tax records, mafia connection, prostitutes, his mental illness) is eventually going to give, and he will publicly implode into the failed joke he really already is. (But might still win against the wreckage of the HMS Hillary Clinton.)
If there was any of that I'm sure Bush or Cruz would have already found it. Hell the entire washington establishment was against him during the primary if they couldn't get a silver bullet what makes you think all of a sudden Hillary's folks can do better? Heck in 2008 she couldn't even get nothing to take down Obama.
Really though Trump and a mafia connection would be great. "Teflon Don"
There was a lot of talk a while back of how there was essentially no opposition research done on him during 2015 as nobody was taking him seriously; as a result there may still be plenty of time for stuff to come out.
Though, given the track record so far, I have no idea what could actually do him in, short of hard evidence of ritualistic killings or something.
