As the midterm elections draw nearer, the odds that Robert S. Mueller III, the special counsel, will spearhead any major developments in the Russia investigation before Election Day grow steeper and steeper. The Justice Department generally does its best to avoid taking action in such a way that it might influence an election — even as the president tweets defiantly that there was “No Collusion!” Functionally, this means that voters will likely be left to make up their minds about how seriously to take the possibility of collusion without any further guidance from the special counsel’s office.

So if Mr. Mueller remains silent, what is there to say at this point about how the pieces of the Russiagate puzzle fit together? To start with, even the president has now acknowledged on Twitter that Donald Trump Jr. met with a Kremlin-linked lawyer at Trump Tower for the purposes of gathering dirt on Hillary Clinton. Whatever President Trump tweets, this would seem to fall squarely into the category of collusion — which may explain why some of the president’s more fervent supporters have begun suggesting that any help Russia provided in defeating Mrs. Clinton should be celebrated.

Between extensive reporting and the work of the special counsel’s office, we have a detailed — though incomplete — sense of how the Russian effort fit together. The Kremlin orchestrated a widespread social media campaign along with the hacking and leaking of emails from the Democratic National Committee and John Podesta, Mrs. Clinton's campaign chairman. It reached out to Trump aides like George Papadopoulos, Roger Stone and, yes, Donald Trump Jr.

So there was plenty to collude with. And judging by Mr. Trump Jr.’s eager response to the offer of dirt — “If it’s what you say I love it, especially late in the summer,” he wrote to the music producer who brokered the meeting — there was plenty of willingness on the Trump campaign’s side. The real question is whether that eagerness ever added up to a systematic outreach, and if so, how high up that outreach originated.