Here goes...
Coordination is what happens when an ostensibly independent group makes expenditure decisions, or ad content decisions in direct consultation with the candidate that it is trying to help. That's sort of a lay-person definition. So, superPACs aren't allowed to coordinate with candidates. They can run ads that are clearly on a candidate's behalf, but they can't have the head of the superPAC sit down with the candidate, map out where the ads will run, when, how the ads will look, scripts, etc. That would be coordination. Legal problems ensue. Here's the thing, though. Nobody ever gets caught for coordination in the campaign finance system. Why not? It's too easy to accomplish the same goal without actually crossing the legal threshold. Basically, superPACs and other independent groups all play a game of "I'm not touching you!" with the FEC.
The kind of example I always give when I teach this stuff is the basic signaling process that occurs any time a candidate talks. Hey everyone! Pay attention to X about my opponent! Did you hear about that scandal?! If a superPAC then runs ads about X, is that coordination? Not legally. So, where's the line?
Uh...
Somewhere between that and the working dinner where the candidate and the chair of the superPAC map out the ad campaign in full together. And that leaves plenty of room for smart people to send signals that are clear enough for the superPAC chairs to understand, but vague enough to avoid any legal problems because the laws are written in such a way that you have to be really stupid to go far enough to get convicted.
Any time I use the word, "stupid," do you free-associate the name, "Trump?" Good. Well done.
How stupid is Trump? That sounds like the set-up for an old comedy routine, until you remember that he can launch nuclear weapons. HAHA! ha... uhh...
Trump is very stupid, but he is also full of bluster and bullshit. Could his entreaty to the Russians be taken as bluster and bullshit, given his propensity for those things? As Trump? Yup. That cannot be ruled out entirely, and between that and the high bar for showing coordination in campaigns, how much should you read into this? Not much.
Not much, but not nothin'. Here's the what-if. What if the Russians had found the deleted emails, and what if they had something other than just details on Chelsea's wedding, and other such irrelevancies? What if they handed those emails to Trump, or to WikiLeaks, via Trump's good buddy, Roger Stone? Trump would have been pretty happy about that. And he's already pretty enamored of Putin. It would have been one more way for the Russians to give him something.
Anyway, keep this in mind when thinking about the latest indictments. "Coordination" in campaigns is kind of a joke because the legal threshold for demonstrating it is so high. Of course, I essentially advocate no limits on donations, with full disclosure of all sources. If you think there is influence, you know exactly what you are getting. Trump basically had a Russian flag on him while campaigning for office, so we shouldn't be surprised that one of his first acts as President was handing national security secrets to the Russians just because he could. No, I don't forget these things, and neither should you.