Question:
Now for the other letter.

Does it follow that "There was only one letter."?
Answer:
no

Question:
What if the Commission chose to ignore this divergence in costs and hit First-Class mail with a larger increase?

Does it follow that "What if the Commission chose to ignore this divergence in costs because of pressure from Congress?"?
Answer:
it is not possible to tell

Question:
In lieu of metal detectors, Safe Teams of faculty and police target troubled students.

Does it follow that "Safe Teams are effective."?
Answer:
it is not possible to tell

Question:
If they learn of the caves we're going to be fighting with our backs to the wall.

Does it follow that "Once they know about the caves, we're done for. They'll know of them and use them against us."?
Answer:
it is not possible to tell