This meeting, which didn't involve anyone from the Trump campaign until it did, keeps adding more Russian participants, including a former Russian secret agent. The ever-changing narrative from Donald Trump, Jr. could be just innocent omissions, as he claims, or important details linking these contacts to possible collusion. Whatever the case, further exploration by the appropriate congressional committees and the special counsel seems more than warranted. Opening this can of worms might just make some powerful people squirm.