Remember how her approval ratings shot sky high when the Monica affair was first made public and she played the role of the wronged woman?
So does she.
She also saw how good the sympathy factor worked for her when she shed a few crocodile tears in New Hampshire so she agreed to discuss Monica on national TV to remind the suckers that she is the loving wife who was wronged by the bad boy husband and the harlot and get those sympathy votes flowing.
Everyone KNOWS what a cold, calculating witch she is and that this subject would never be broached in an interview without her prior agreement.
And she wouldn't agree if she didn't she an upside effect on the voting.