Answer (Thanks Harrije)
Answered in 6x16. Jacob told Widmore that due to his resistance to EM energy, Desmond was a "failsafe" to ensure that the MIB's plan would fail.
Answer (Thanks Harrije)
Answered in 6x16. Jacob told Widmore that due to his resistance to EM energy, Desmond was a "failsafe" to ensure that the MIB's plan would fail.