I suspect it'll take considerably more than this to sink Kerry.
This is just another brick in the boat...
IF the witnesses hold to their story, then the Dims have a candidate, the presumptive nominee, who attended a meeting where the assassination of U. S. senators was debated and voted on, and he never reported the assassination plot to authorities. Now we learn that he continued to associate with that organization.
It may take a while to repeat this enough so it sinks in, but if we don't let up, he's toast.