>> plus, the republican race towns for the battle over isis. >> we hear senator paul said isis exists because of republican foreign policy hawks. that is ridiculous. the senator is unsuited to be our commander and chief. >> our sunday panel weighs in on the foreign policy showdown heating up the republican field. all right now on "fox news sunday." >> hello again from fox news in washington. we begin with breaking news. vice president biden's son has died of brain cancer at age 46. the vice president's office said he was first diagnosed in 2013. he was treated and given a clean bill of health before it returns this spring. beau biden was the former attorney general of delaware and announced last year he would run for governor in 2016. when biden was just three he and his brother hunter, were seriously injured in a car crash that killed his mother and infant sister.