Premise:
"But the supply-siders are quite right when they say that economies are not a zero-sum game."
Hypothesis: Economies are very complicated and cannot be reduced to a zero sum game.

it is not possible to tell

Premise:
"13 Some federal agencies, such as the Social Security Administration (SSA), are exploring new ways to involve employees by devolving decisionmaking authority."
Hypothesis: Some federal agencies, such as the Social Security Administration, are exploring new ways to involve employees

yes

Premise:
"At some point, I'd get off the train and continue on my way."
Hypothesis: I would not spend the rest of my life on the train.
yes