To begin with, long, long ago - in the spring of 2016, the Obama Administration somehow determined that "Russia" was meddling in the US election process. It kept this news private and claims to have confronted Russia over its interference by - get this - asking them to stop. That's right - they didn't stop - that is, if they were doing anything in the first place, for there is no credible evidence that they had been. As far as is known, the extent of their interference was to be a conjectural source of the hacked and stolen emails from the Democratic National Committee and Clinton/Obama operative John Podesta. Of course, there is no evidence that it was "the Russians" who did this is, which is why we use the word "conjectural."
For reasons good or bad, President Trump fired FBI Director James Comey, and Mr. Comey testified to Congress earlier this month. He said things that pleased and upset critics and defenders of President Trump alike, but he also said that after eleven months of investigating the FBI could find no evidence of collusion between the Trump Campaign and Russia. MSNBC's Chris Matthews, a fierce critic of President Trump, said that Mr. Comey's testimony means that the "collusion" story "falls apart." What's more, former President Obama, former Vice President Biden, James Clapper and John Brennan, respectively the Director of National Intelligence and the CIA Director in the Obama Administration and Democratic Senator Diane Feinstein earlier all had declared that the Russians did not "hack the election" and there was no evidence of collusion.
It bears repeating - if the Obama Administration or the Clinton Campaign had evidence that the Trump campaign was colluding with Russia, they would have loudly proclaimed it. They used every other tool against Mr. Trump that was at their disposal, and they didn't much care if the charges or stories were true or not. Any campaign that had information that the opponent was working with a foreign power would surely have disclosed it. It could well have turned the election. The fact that they did not disclose it may be, as they claim, because they did not want to "upset the applecart" in case of a Clinton victory. Or it may be that there was nothing to disclose, that there was no collusion. So, along the lines of the horror movie title above, now we are at the Sherlock Holmes case of "The Dog That Didn't Bark." And that lack of a Russian accent to the bark, when it could have clinched the election, is the most compelling point against the existence of any Trump-Russia connection involving the 2016 Presidential election.