I can't help but wonder why some of this stuff IS just coming out now. Wiki-leaks had the info on Clinton's speeches all along, didn't they? So, what would have happened if they'd released that during the primaries? Maybe nothing, but there's have been a chance for a different candidate. Same for the Trump video. Who does it help to release this stuff between the conventions and the election? (Serious question.)
It's the "October surprise" effect. Usually "October surprise" is used for other events, but it fits for this too.
Politically speaking, the "best" time to really go after a candidate, or to seek to influence the election in any way, is in October, because they will least likely be able to recover in time before the election. During the GOP primary, those of us against Trump knew stuff like this that would likely be big stories.... in October. We knew they would sit on the very worst things and then release it then, because much of the media does not favor Trump, and he would be less likely to rebound prior to election day. People were trying to advocate with the media to release all of this kind of stuff and much more much sooner. They wouldn't. So many people tried.
One of the arguments reporter gave back is that if they released too much too soon, Trump would rebound anyhow during the primaries and win the general election because they would have nothing left to throw at him in October.
I disagree with that logic and so do most decent journalists... but they don't make the final decisions.
In typical election cycles, most people don't pay that much attention during primaries, and if someone is trying to sell newspapers, October is the time. The balance to that is the hope that the parties will actually vet their own candidates themselves, and pick decent humans. Trump was researched by so many and it's not news to most primary voters he is a misogynistic bully. It was surprising so many wanted to believe he could beat Hillary despite that fact. Same with Clinton. Her wall street ties are news, but the tangible headline grabbing transcripts are news now.
It does not help the country very much for media to wait. It helps one party go after the other party, it helps anyone who wants to do someone else harm and/or get the most attention to the matter.
The October surprise effect is why WikiLeaks waited too. They had the speeches long before all of this... I know some Trump supporters who were waiting and waiting for them to be released sooner.
Even North Korea gets involved in the October surprise effect. Every 4 years, in October, North Korea releases their most scary threats against the US in order to try to influence the election and get our maximum attention.
What surprised me with this story about Trump is that they released it on a Friday, which is when someone should release a story they want to bury. If someone wants to maximize the impact of a story, then they release it on a Monday or Tuesday and they let cable media freak out all week about it. Release on a Friday, and it has less of an impact.