Hi uptowngirl92,
The passage tells us that experience is not necessary for running a solid foreign policy. Then it goes on to tell us that anyone with an acute political sense, disciplined temperament, and good ability to absorb and retain information WILL run a solid foreign policy. This does not mean that politcal sense, disciplined temperament, and ability to retain info are necessary for running a good foreign policy. Instead, it means that those things are sufficient. For example, being in New York is sufficient to conclude you are in the US, but it is not necessary to be in New York in order to be in the US.
I should add that LSAT loves testing the distinction between sufficient and necessary conditions but that GMAT rarely tests it.