Sentence 1: Both the external and internal environments are important, and neither can be viewed independently of the other.

Sentence 2: It has long been held in this industry that there's a relationship between the internal and external environments that can't be underestimated.
Is this second sentence entailed by the first?

Answer: it is not possible to tell

Sentence 1: Is it possible?

Sentence 2: Is it doable?
Is this second sentence entailed by the first?

Answer: yes

Sentence 1: So Clinton wouldn't perjure himself and, as I argued Sunday, an apology is likely to kill the appetite for any impeachment hearings (over obstruction, Whitewater, Filegate, etc.).

Sentence 2: An apology by Clinton will not make it less likely for him to get impeached.
Is this second sentence entailed by the first?

Answer:
yes