[gdani]

There would be a coup if she got elected

While it wasn't Bhutto who was overthrown, that's how Musharraf got where he is today.

[Marano NYC]

This would complicate the war on terror. Bhutto is not a USA fan but not liked by the Islamisist. She could crack down on the militants and be an asset. However, she would also force a larger contingent underground.
She would likely improve relations with India. This would complicate our efforts in Afghanistan