Was the second assassination attempt against former President Donald Trump preventable? A whistleblower is the latest to say yes — and Sen. Josh Hawley of Missouri wants answers. According to a letter from Hawley to the acting director of the Secret Service last week, the whistleblower has “direct knowledge of Secret Service protection” where attempted assassin Ryan Routh was allegedly able to lie in wait for hours with a firearm before his detection. In the letter, Hawley said that, if true, protocols stipulated that Routh “should never have been able to linger around the course for that lon…