Suppose for a moment this was not a lab leak. What kind of evidence would be sufficient to be convincing? Or are we looking for investigation after investigatio

Suppose for a moment this was not a lab leak. What kind of evidence would be sufficient to be convincing? Or are we looking for investigation after investigation until the end of time? What this letter fails to establish is a success criterion. Nobody is going to invest in a "proper investigation", much less one tinged with politics, without even knowing something will come out of it.