Brinkley worked assiduously to join Beschloss and Doris Kearns Goodwin on the air.
Brinkley did not work hard to get on the air with Beschloss and Goodwin.  
mnli hypothesis: Brinkley did not work hard to get on the air with Beschloss and Goodwin.   premise: Brinkley worked assiduously to join Beschloss and Doris Kearns Goodwin on the air.