Says American people need to learn 'truth'
Tells 'Meet the Press' host Chuck Todd where that leads is another matter
Russian election interference puts exclamation point on need for holistic approach
But says no evidence of U.S. collusion or effect on election outcomes to date
Facebook, Twitter, and Google execs lined up for Sept. 5 hearing
Points to absence of accusations rather than voluminous evidence of meddling
Says they could abetted by media quick to drive clicks and ratings
Facebook CEO pledges fixes to privacy, political advertising issues